Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: shadowblade on March 08, 2014, 03:10:43 pm
-
I've been doing a rough 'window test' on a number of different papers over the past six months to estimate the long-term stability of their inkjet coatings, owing to the very limited information regarding this out there (as opposed to information on lightfastness).
Basically, I mounted a number of pieces of paper onto the inside of a north-facing window and let them bake over the Australian spring and summer (using Blu-Tack, so that the paper wasn't actually touching the glass) and checked on them from time to time to see how they held up. Humidity and temperature fluctuated as they would in an un-airconditioned home environment (I was away most of the time, so heating/air con were left off for the most part). Not all that rigorous, I know, but good enough to get an idea of what to expect.
The papers tested were:
Fuji Crystal Archive (resin-coated chromogenic)
Moab Slickrock Metallic Pearl (resin-coated)
Hahnemuhle Photo Glossy (resin-coated)
Hahnemuhle Photo Rag Baryta (baryta)
Ilford Gold Fibre Silk (baryta)
Hahnemuhle Photo Rag Pearl (cotton rag)
Hahnemuhle Photo Rag (cotton rag)
Canson Etching Edition (cotton rag)
All of them except the Fuji Crystal Archive included one unsprayed piece and one piece sprayed with Hahnemuhle Protective Spray.
The results?
- After two months, the Fuji Crystal Archive had curled up so badly that it fell off the Blu-Tack; trying to uncurl it merely resulted in the polythene layer cracking across the entire width of the sheet.
- After three months, the receptive layer on the unsprayed RC inkjet papers had both disintegrated to the point that merely touching it caused the layer to come off onto the finger as a powder. The sprayed RC papers held up better, but were still showing some signs of flaking (i.e. the inkjet layer was coming off the resin layer, but was being held together at the front by the spray). After five months, the sprayed RC papers were also flaking badly, with large flakes falling when touching the paper.
- After six months, the baryta papers were also curling, delaminating, flaking and cracking. Again, the sprayed sheets held up better than the unsprayed sheets. The Hahnemuhle Photo Rag Baryta also held up much better than the IGFS. I couldn't tell whether it was the inkjet layer coming off the baryta layer or the baryta layer coming off the paper base. I suspect it may have been the latter, given that the paper base would have been shrinking and expanding with changes in humidity while bound to the rigid, inflexible baryta layer.
- The cotton rag papers held up much better than the others. Not surprising, really, given that these essentially consist of a thin, relatively-flexible coating of polyvinyl alcohol and silica directly bonded to a thicker and less-flexible paper base, with no in-between layer. At six months, I didn't notice any peeling or cracking in either the sprayed or unsprayed samples.
Obviously this is a quick test rather than a detailed scientific study - I'm still not certain about the long-term durability of any of these coatings, but at least know which types are the better ones.
Does anyone know what sort of surface sizing Hahnemuhle and Canson use in their papers, prior to inkjet coating? If they size their papers with polyvinyl alcohol, it would make make sense for the coating-paper bond to be even stronger - after all, the coating and the paper's external size would be the same material. Although it could just be that a thin, flexible PVOH layer can conform to an expanding and contracting paper base much better than a rigid baryta or resin layer can, and that PVOH just doesn't stick all that well to plastic...
-
Nice test!
Thanks for posting.
-
Fading from of UV light is sort of accumulative, exposing to very bright UV light does translate to a somewhat effective age acceleration test. Heat on the other hand is not accumulative. Placing the prints in the manner you describe seems a very abnormal condition with temperatures much greater over sustained periods of time, and while certainly informative in some circumstances, I don't think you can draw any real conclusions, unless you expect the prints to be in a similar environment. Sitting right against a sunlit window doesn't sound like the type of thermal characteristics one would expect a print to be in ... maybe a sign or poster, but not a quality photograph created for exhibit. As an example, RC prints that are decades old do not exhibit the kinds of issues you have describe unless they have been subjected to unusual storage conditions, so how does your test correlate? I have had a fuji flex print sitting in the east facing window of my store for about a year, and it is showing signs of fading, but no physical issues at all.
Unfortunately I don't believe there is a way to do an "accelerated deterioration test", but then again the conditions of any environment go beyond just light and heat, and are wildly variable.
-
Fading from of UV light is sort of accumulative, exposing to very bright UV light does translate to a somewhat effective age acceleration test. Heat on the other hand is not accumulative. Placing the prints in the manner you describe seems a very abnormal condition with temperatures much greater over sustained periods of time, and while certainly informative in some circumstances, I don't think you can draw any real conclusions, unless you expect the prints to be in a similar environment. Sitting right against a sunlit window doesn't sound like the type of thermal characteristics one would expect a print to be in ... maybe a sign or poster, but not a quality photograph created for exhibit. As an example, RC prints that are decades old do not exhibit the kinds of issues you have describe unless they have been subjected to unusual storage conditions, so how does your test correlate? I have had a fuji flex print sitting in the east facing window of my store for about a year, and it is showing signs of fading, but no physical issues at all.
Unfortunately I don't believe there is a way to do an "accelerated deterioration test", but then again the conditions of any environment go beyond just light and heat, and are wildly variable.
This wasn't a thermal test. It was a test of how a print would handle in a non-museum home or commercial environment after exposure to UV light - specifically, due to embrittlement of the inkjet coating or other layers, or due to failure of bonds between the layers. After all, everyone knows that inkjet papers start off flexible, but we don't really know whether they'll stay that way with UV exposure. It's like gesso or paint coming off an old oil-on-canvas painting as it stretches and sags on its frame during changes in humidity. For this reason, I also flexed the paper in each direction every month to see if anything flaked off.
Temperatures experienced by the paper ranged from 8-40 degrees Celcius - normal conditions around here. Relative humidity ranged from 20-95%. With regards to pollutants, it was indoors, in the middle of a big city. So, no unusual environmental stresses there - just what you'd expect in a typical home environment, but with accelerated UV exposure.
-
As Wayne points out, you didn't just "accelerate" UV exposure, you also subjected it to direct sunlight millimetres from glass. That would have significantly impacted the heat levels on the media compared to a normal presentation hanging on a wall inside a home.
This is nothing like the environment in which most prints will exist, being either mounted to a board or behind glass or both, and sitting on a wall out of direct sunlight most of the time and certainly well away from an external window.
You also had the media without an ink load, which may also impact (I don't know, but it's a pretty key difference so it shouldn't be ignored).
As an Aussie, I can attest to the fact that putting your face against a North facing window in summer when it's hot is extremely uncomfortable - I dare say you could burn yourself (not just sunburn) with any prolonged exposure. We also have higher UV levels here than most other parts of the world, so the total impact on the media is quite extreme an unrealistic.
-
As Wayne points out, you didn't just "accelerate" UV exposure, you also subjected it to direct sunlight millimetres from glass. That would have significantly impacted the heat levels on the media compared to a normal presentation hanging on a wall inside a home.
Surprisingly not. In the afternoon of the hottest day of the summer (44 degrees outdoor shade temperature), with no cloud cover and light streaming in through the window, the papers all measured between 37 and 39 degrees Celcius. This is because the near-white papers reflected most of the incoming solar radiation. In contrast, the black silicone sealant around the window measured at 88 degrees Celcius at the same time.
If I had printed the sheets, no doubt the temperature would have been a lot higher.
In any case, short periods of high temperatures are normal for photos and paintings displayed in home environments if they're displayed in any location that receives direct sunlight. Usually, a photo's location is chosen for aesthetic and interior design reasons, not print preservation concerns, and many of these locations receive direct sunlight at some time of the day at some point in the year. It's only museums, galleries and collections that deliberately locate works away from sunlight. And it doesn't take a lot of direct sunlight from an cloudless sky on a hot day to heat a printed image - often with dark inks, and usually stored inside an enclosed frame that essentially acts as a greenhouse and traps heat - to 50-60 degrees or hotter.
This is nothing like the environment in which most prints will exist, being either mounted to a board or behind glass or both, and sitting on a wall out of direct sunlight most of the time and certainly well away from an external window.
Blasting a print with 50klux xenon lamps for 12 or 24 hours a day also isn't anything like the environment in which most prints would be displayed. The point of accelerated testing isn't to simulate the environment the prints are going to be kept in - the only way to do that would be to hang sets of prints in various places for 50/100/200 years and see what happens. It's to simulate what will happen to paper when it's subjected to real-world fluctuations in humidity and temperature, as well as movement/flexion, after its been blasted by UV radiation to the equivalent of 50/100/200 years in normal display. In other words, what will happen to the paper when its been on display for a few decades and you then try to change the mat/frame, unframe it and send it by courier, move it to a new place or otherwise handle it in any other way, or what will happen to even a framed, unmoved print given a bit more time and normal humidity-related paper fluctuations.
You also had the media without an ink load, which may also impact (I don't know, but it's a pretty key difference so it shouldn't be ignored).
I was debating whether to run the test with or without ink. In the end, I went without ink because I didn't want temperature to become an issue (dark surfaces can become 30-40 degrees hotter than light-coloured surfaces in the sun) and because every print will have areas of light or no coverage (e.g. the print borders, at least a narrow strip of which won't be covered by the mat). If these light/no coverage areas fail, then the print as a whole has failed, whether the heavily-inked parts are OK or not.
As an Aussie, I can attest to the fact that putting your face against a North facing window in summer when it's hot is extremely uncomfortable - I dare say you could burn yourself (not just sunburn) with any prolonged exposure. We also have higher UV levels here than most other parts of the world, so the total impact on the media is quite extreme an unrealistic.
UV exposure here is definitely higher, but that's just like deciding to use 50klux lamps for permanence testing instead of 20klux lamps. Both are valid. Naturally, you can't directly compare results from a 50klux test against a 20klux test (due to the possibility of reciprocity failure), but, when you're testing multiple samples against each other, in the same environment, you can safely say whether one particular paper performs better or worse than another. In other words, the results are more qualitative rather than quantitative, but you can say the same for most accelerated testing regimes, since speeding up the UV illumination doesn't speed up gas fading, dark fading, humidity and biological effects which also deteriorate the print.
-
Obviously this is a quick test rather than a detailed scientific study - I'm still not certain about the long-term durability of any of these coatings, but at least know which types are the better ones.
Does anyone know what sort of surface sizing Hahnemuhle and Canson use in their papers, prior to inkjet coating? If they size their papers with polyvinyl alcohol, it would make make sense for the coating-paper bond to be even stronger - after all, the coating and the paper's external size would be the same material. Although it could just be that a thin, flexible PVOH layer can conform to an expanding and contracting paper base much better than a rigid baryta or resin layer can, and that PVOH just doesn't stick all that well to plastic...
Not scientific but still interesting.
I think that the compatibility of the sizing and the coating medium could have an influence (does not even have to be the same "glue") but you also should count the roughness of the paper base at the bond level. Not only does a rougher surface increase the bond's surface but its geometry also dampens the expansion and shrinking forces over the total surface. A smooth paper based inkjet paper has a more uniform layer structure, say planes on top of one another that have more problems with heat/humidity expansion differences. I feared that the polyethylene barriers in RC paper would create an issue on the coating bond anyway, PE is quite inert and needs Corona treatment to create a better bond for inks and glues. Even then a weak bond. If the coating is not much more than gelatine or PVA like in analogue photo papers then the flexibility of coating will cope as long as that flexibility is kept, it will be harder when minerals are introduced in the coating like it is done in the inkjet coatings we use today. That the fiber/baryta papers are not free of mechanical wear is interesting too. The sizing compatibility should not be that different to that of the cotton papers.
Your paper summary is a bit confusing. Barytes are used in papers without them mentioned in the product name and the Photo Rag Baryta is a cotton paper. There might be a relation between the roughness of the paper base (most cotton but also some alpha cellulose qualities are rough at the base) and the compensation of expansion etc. For smoother inkjet paper surfaces there is a distinction between creating them on smooth paper bases or creating a smooth surface on rougher paper bases, say only satinised after applying the inkjet coating and not twice in the inkjet paper creation. A rougher backside can give an indication though it is possible to make a paper base with one side (hot press) satinised while the other side keeps a rougher surface.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots
-
Another interesting study would be to rerun your test only behind a piece of museum glass. It would eliminate 99% of the worrisome UV content and allow you to study the temperature/moisture issues without the confounding issue of UV exposure. My hypothesis is that you will induce very nearly the same results even without the UV component present. The key antagonist in this test is the severe heat/desiccation cycling caused by the lack of moisture control at the sample plane. All print media are very hygroscopic in nature. 40% RH at normal room temperature represents the ideal internal moisture content for essentially all of the media you tested. Expansion/contractions caused by moisture changes in these hygroscopic materials are typically 10 times greater than that caused by temperature change, and those severe dimensional mismatches between the layers lead to severe internal mechanical stresses. With traditional photographic gelatin (i.e the Fuji Crystal archive image bearing layer) for example, the contracting gelatin layers can place a huge tensile stress on a rigid support layer (glass or polyester, for example) of over 6000 psi. Dry gelatin coatings are stronger than epoxy coatings! When the sunlight cycle is over, the nighttime cycle starts to cool and rehydrate the coatings and base, but some hysteresis in the dimensional properties still remains, i.e., it doesn't return to precisely the same dimensional configuration where it initially started. Then the next sunlight cycle induces the stress cycle all over again. Micro cracks start to form which ultimately propagate into larger cracks. It take much less energy to propagate an existing crack than to form it initially. Adhesion between coatings and base gets damaged for the same reasons.
When the sun bakes these materials to 40C+, the moisture content will drop to a level well below that encountered in normal daily indoor environments (i.e. equivalent of less than 5% RH indoor prolonged humidity level). That said, this "accelerated" test does bear some rough chemical/physical relationship to what can/will happen to coated media in long term keeping conditions where strong seasonal cycles are present (albeit taking these materials well beyond their rational mechanical limits, kind of like when you bend a print to the point of creasing it). So, in very rough terms your six month/180 day test is something like 180 years of severe seasonal cycling, i.e, keeping a photograph with no moisture barrier protection in a home that has no HVAC system to regulate humidity, just supply indoor heat during the winter but no cooling/dehumidification indoors during the summer. Now you can understand why museum experts attempt to control indoor environments more tightly in order to better preserve important artistic/historic works. Homeowners with fine art/historic collections in their possession should consider some HVAC upgrades as well. And don't put your fine art, whether it be photograph, painting, or uncoated paper in a window :)
cheers,
Mark
http://www.aardenburg-imaging.com
-
Interesting test,and thanks for carrying it out. However, I suspect that putting the prints that close to the glass created a micro-environment between the print and the glass that was much much hotter than the ambient temperature. You're creating a heat trap since there's no possibility of air circulation carrying away the hot air on the surface of the print. I think a better test would be to have the prints a foot or two away from the window. But very interesting results nonetheless.
-
My hypothesis is that you will induce very nearly the same results even without the UV component present. The key antagonist in this test is the severe heat/desiccation cycling caused by the lack of moisture control at the sample plane. All print media are very hygroscopic in nature. 40% RH at normal room temperature represents the ideal internal moisture content for essentially all of the media you tested.
Mark, I totally agree with your hypothesis. I'm regularly ironing my prints and my observations were 99% consistent to shadowblade test results - PE type papers crack very easily, baryta papers with anti-curl layers can also be destroyed, Hahnemuehle baryta papers and matte calendared are most heat-resistant, while matte heavily textured papers can also be problematic.
-
I'm curious if you observe, with the matte rag papers, Hahnemuhle Photo Rag and Canson Etching Edition, any tendency for the clay-like receptor coating to become more powdery, flaky, or lose it's physical integrity or in any way. Might require some slight abuse to induce anything noticeable?
I found the test info useful, it all helps.
Thanks,
Tyler
-
I think the test would have been more educational had the same image been printed on each paper and then the images all mounted on a board that was 12' away from the window getting full sunshine.
The intense heat that is created through the glass was so artificial an environment that I believe that it corrupted the results. UV is what we are interested in, not 50+C temps.
Just my AUS$0.02 :)
-
I think the test would have been more educational had the same image been printed on each paper and then the images all mounted on a board that was 12' away from the window getting full sunshine.
The intense heat that is created through the glass was so artificial an environment that I believe that it corrupted the results. UV is what we are interested in, not 50+C temps.
Just my AUS$0.02 :)
Interesting test,and thanks for carrying it out. However, I suspect that putting the prints that close to the glass created a micro-environment between the print and the glass that was much much hotter than the ambient temperature. You're creating a heat trap since there's no possibility of air circulation carrying away the hot air on the surface of the print. I think a better test would be to have the prints a foot or two away from the window. But very interesting results nonetheless.
The temperature of the paper, as measured even on the hottest afternoon on the year, never exceeded 37-39 degrees and the circulation around paper Blu-Tacked to the window is much greater than any air circulation you'd have around a framed and matted print.
Besides, *any* print that is put in a location that receives direct sunlight will exceed 50 degrees at some point. Framing and matting a print behind glass is the real heat trap - it functions just like a greenhouse. Solar radiation hits the print and gets absorbed by the darker inks (much more so than white paper - note the reading of 88 degrees on the black surface next to the white paper when it was measuring 39 degrees). The hot paper surface then heats up the air within the frame, which is trapped behind the glass and keeps the print warm for much longer than the period of solar irradiation.
-
Another interesting study would be to rerun your test only behind a piece of museum glass. It would eliminate 99% of the worrisome UV content and allow you to study the temperature/moisture issues without the confounding issue of UV exposure. My hypothesis is that you will induce very nearly the same results even without the UV component present. The key antagonist in this test is the severe heat/desiccation cycling caused by the lack of moisture control at the sample plane. All print media are very hygroscopic in nature. 40% RH at normal room temperature represents the ideal internal moisture content for essentially all of the media you tested. Expansion/contractions caused by moisture changes in these hygroscopic materials are typically 10 times greater than that caused by temperature change, and those severe dimensional mismatches between the layers lead to severe internal mechanical stresses. With traditional photographic gelatin (i.e the Fuji Crystal archive image bearing layer) for example, the contracting gelatin layers can place a huge tensile stress on a rigid support layer (glass or polyester, for example) of over 6000 psi. Dry gelatin coatings are stronger than epoxy coatings! When the sunlight cycle is over, the nighttime cycle starts to cool and rehydrate the coatings and base, but some hysteresis in the dimensional properties still remains, i.e., it doesn't return to precisely the same dimensional configuration where it initially started. Then the next sunlight cycle induces the stress cycle all over again. Micro cracks start to form which ultimately propagate into larger cracks. It take much less energy to propagate an existing crack than to form it initially. Adhesion between coatings and base gets damaged for the same reasons.
I'm not so sure about that. Certainly, the dessication/rehydration cycle is the primary driver of dimensional change in papers. But the primary driver of stress at the interface layer isn't dimensional change per se - rather, it is a product of dimensional change in the paper as well as resistance to dimensional change and flexion in the coating layer. Unexposed to UV light, a polyvinyl alcohol film (even embedded with silica particles) is supple and flexible - this is why we are able to bend and stretch inkjet canvas. But, with prolonged UV exposure, I suspect the layer becomes stiffer and more brittle - it is this resistance to the paper's dimensional change that causes stress to build up along the interface, resulting in failure of the bond, cracking and delamination.
When the sun bakes these materials to 40C+, the moisture content will drop to a level well below that encountered in normal daily indoor environments (i.e. equivalent of less than 5% RH indoor prolonged humidity level). That said, this "accelerated" test does bear some rough chemical/physical relationship to what can/will happen to coated media in long term keeping conditions where strong seasonal cycles are present (albeit taking these materials well beyond their rational mechanical limits, kind of like when you bend a print to the point of creasing it). So, in very rough terms your six month/180 day test is something like 180 years of severe seasonal cycling, i.e, keeping a photograph with no moisture barrier protection in a home that has no HVAC system to regulate humidity, just supply indoor heat during the winter but no cooling/dehumidification indoors during the summer. Now you can understand why museum experts attempt to control indoor environments more tightly in order to better preserve important artistic/historic works. Homeowners with fine art/historic collections in their possession should consider some HVAC upgrades as well. And don't put your fine art, whether it be photograph, painting, or uncoated paper in a window :)
cheers,
Mark
http://www.aardenburg-imaging.com
I suspect the same thing would happen to a framed paper exposed to direct sunlight. After all, there's much more air circulation around an unframed piece of paper than there is in a framed image.
-
The temperature of the paper, as measured even on the hottest afternoon on the year, never exceeded 37-39 degrees and the circulation around paper Blu-Tacked to the window is much greater than any air circulation you'd have around a framed and matted print.
Besides, *any* print that is put in a location that receives direct sunlight will exceed 50 degrees at some point. Framing and matting a print behind glass is the real heat trap - it functions just like a greenhouse. Solar radiation hits the print and gets absorbed by the darker inks (much more so than white paper - note the reading of 88 degrees on the black surface next to the white paper when it was measuring 39 degrees). The hot paper surface then heats up the air within the frame, which is trapped behind the glass and keeps the print warm for much longer than the period of solar irradiation.
Very few prints receive massive amounts of direct sunlight at close range. I'm not sure where you are getting your 50c assumption but not buying it.
I don't know how you measured the temperature of your prints but I wonder if it was scientific enough to really know how hot the actual paper was. Measuring the air around the print isn't the same, and even 40c is pretty excessive. Certainly while short periods of time are not a problem, extended exposure to heat is. I just don't see any correlation to real world situations.
I understand the desire to test the paper itself and the bonding of the coating to the paper, but exaggerated test conditions really don't work that well. That's one of the real concerns about print longevity ... we can test the fade characteristics of the ink set, and to some degree the deterioration of other factors from UV and perhaps ozone, but simulating all the other environmental issues a print might go through is problematic.
I've done many fading tests like this over the years ... back window of my car, window of my shop, and any circumstance which allows enough sunlight to fade images quickly also subject the print to temperature extremes. The prints always curl or sort of fall apart ... something I don't see with many decade old prints that haven't been subjected to the same treatment.
-
Not scientific but still interesting.
I think that the compatibility of the sizing and the coating medium could have an influence (does not even have to be the same "glue") but you also should count the roughness of the paper base at the bond level. Not only does a rougher surface increase the bond's surface but its geometry also dampens the expansion and shrinking forces over the total surface. A smooth paper based inkjet paper has a more uniform layer structure, say planes on top of one another that have more problems with heat/humidity expansion differences. I feared that the polyethylene barriers in RC paper would create an issue on the coating bond anyway, PE is quite inert and needs Corona treatment to create a better bond for inks and glues. Even then a weak bond. If the coating is not much more than gelatine or PVA like in analogue photo papers then the flexibility of coating will cope as long as that flexibility is kept, it will be harder when minerals are introduced in the coating like it is done in the inkjet coatings we use today. That the fiber/baryta papers are not free of mechanical wear is interesting too. The sizing compatibility should not be that different to that of the cotton papers.
I think the polythene layer is problematic for two separate reasons. Firstly, the bond with the inkjet layer is weak, allowing the inkjet layer to easily flake off or crumble. Secondly, its rigidity in comparison with the paper base causes great stresses when the paper expands and contracts with humidity; these stresses can lead to cracking or warping of the RC layer.
Your paper summary is a bit confusing. Barytes are used in papers without them mentioned in the product name and the Photo Rag Baryta is a cotton paper. There might be a relation between the roughness of the paper base (most cotton but also some alpha cellulose qualities are rough at the base) and the compensation of expansion etc. For smoother inkjet paper surfaces there is a distinction between creating them on smooth paper bases or creating a smooth surface on rougher paper bases, say only satinised after applying the inkjet coating and not twice in the inkjet paper creation. A rougher backside can give an indication though it is possible to make a paper base with one side (hot press) satinised while the other side keeps a rougher surface.
I suspect this is due to the inflexibility of the baryta layer. The paper expands and contracts with changing humidity, but the baryta layer doesn't. This causes stress at the interface between the paper and the baryta layer; given that the baryta layer is so thin, it can't take the stress and begins to crack or delaminate. The inkjet layer on top of the baryta probably holds up just fine - it's the baryta layer that fails, taking the inkjet layer with it.
-
You presumably measured the media temperature as a spot measurement on the side away fro the glass, which could be significantly different to the surface facing the glass. That differential, for starters, could have caused significant issues.
Those temperatures are hugely different from prints behind glass mounted on a wall some distance from the window, even if they get direct sunlight for some period of the day.
-
Very few prints receive massive amounts of direct sunlight at close range. I'm not sure where you are getting your 50c assumption but not buying it.
There's no 'close range' when it comes to sunlight. It all comes from the same source 150 million kilometres away. If an object is receiving direct sunlight, it makes no difference whether it's 1cm away from the glass or 10m behind it. A print on a north-facing wall 3m away from the window receives just as much sunlight and gets just as hot as the same print right up against the window - just that the print on the window will be irradiated for longer than the print on the wall (due to the movement of the sun's relative position in the sky).
It's fairly logical, really. If you put a print inside a frame, you've created a close environment with minimal air circulation. Dark objects (e.g. prints) absorb much more radiation, and become much hotter than, light-coloured objects. This heat has to go somewhere. The print absorbs heat from the sun and, in turn, heats up the air in the frame. This air is trapped there and has nowhere to go - it just gets hotter and hotter.
If you don't believe me, try sitting in a small room with lots of sunlight on a hot day, with the door closed. Then do the same thing in a large room with lots of sunlight and the doors open for air circulation. I can guarantee that the small room will heat up a lot faster than the large room.
I don't know how you measured the temperature of your prints but I wonder if it was scientific enough to really know how hot the actual paper was. Measuring the air around the print isn't the same, and even 40c is pretty excessive. Certainly while short periods of time are not a problem, extended exposure to heat is. I just don't see any correlation to real world situations.
Infrared thermometer. The same one I use for measuring body temperatures of patients, as well as measuring the temperature of heated metal. It doesn't measure air temperature - it measure temperature through the blackbody radiation of the surface.
I've done many fading tests like this over the years ... back window of my car, window of my shop, and any circumstance which allows enough sunlight to fade images quickly also subject the print to temperature extremes. The prints always curl or sort of fall apart ... something I don't see with many decade old prints that haven't been subjected to the same treatment.
The amount of solar radiation you get in 3 months over the spring/summer is equivalent to a lot more than a few decades of typical use.
-
You presumably measured the media temperature as a spot measurement on the side away fro the glass, which could be significantly different to the surface facing the glass. That differential, for starters, could have caused significant issues.
I'd strongly disagree on this. A piece of paper is thin enough that the temperature on one side is much the same as the temperature on the other side, after its been heated for a while.
Try holding a cup of coffee in a (non-ribbed) paper cup. Pretty soon, it becomes far too hot to hold.
Those temperatures are hugely different from prints behind glass mounted on a wall some distance from the window, even if they get direct sunlight for some period of the day.
I agree. Prints - especially dark prints - mounted behind glass away from the window get a lot *hotter* than white paper mounted outside glass.
That's why the surface on my black leather sofa (well away from the window) gets to 50-60 degrees on a hot afternoon, when it is hit by direct sunlight. Trapping it behind glass only makes it hotter.
-
I'm curious if you observe, with the matte rag papers, Hahnemuhle Photo Rag and Canson Etching Edition, any tendency for the clay-like receptor coating to become more powdery, flaky, or lose it's physical integrity or in any way. Might require some slight abuse to induce anything noticeable?
I found the test info useful, it all helps.
Thanks,
Tyler
I'm not sure. Internal stress within the receptor coating is mostly due to expansion and contraction of the paper. How the layer copes with this stress (whether by cracking, peeling or simply bending and conforming) depends on whether the layer stays flexible or becomes rigid and brittle with UV exposure. There was a lot of cracking and other problems in the papers with a rigid layer between the coating and paper (the RC and baryta papers) but none that I saw in
I think it would be a useful test to form a sheet composed purely of UV receptive coating (e.g. a 1mm-thick layer of Inkaid), allow it to dry and then see what happens when it is exposed to UV light and atmospheric pollutants - whether it retains its flexibility, or becomes stiff and brittle.
If it holds up well, an inkjet 'paper' consisting of a 1mm thick film of inkjet coating, with a white polyester mesh embedded within it for whiteness and strength, might be worth considering.
-
Your own logic is defying you :-)
If the white paper reflects a lot of energy, then it can't be as hot on the "dark" side of the paper (not facing the sun) as on the "light" side of the paper (facing the sun and reflecting energy), furthermore, you have a very small layer of air between the paper and the glass which will be heated up and stay hot and without any direct convection won't move a lot. On the "dark" side you have an entire room and thus don't get a layer of air trapped. Furthermore, the glass itself, whilst transparent, will become at least warm and again act as a thermal mass, tending to keep that side hotter.
Sure, if you hold a paper cup for a while (thinner than most media, but I guess comparable) it gets too hot to hold over time. Dip your finger into the liquid and it will burn you right away.
It's true that at some part of the day, a print on the wall may receive almost as much energy as a print on the window (less that lost due to passing through the glass and the related heat into the air etc) but as you noted, the exposure time for direct sunlight will typically be far less and it has the advantage of the thermal mass of the mounting and the frame and, to a lesser degree, the air behind it and the wall. The temperature of the print is likely to be more consistent throughout the day and througout the substrate itself (i.e. less differential most of the time from one side to the other). This is important when considering expansion and contraction of different materials at different rates. More consistency, less extremes = less effect. If that wasn't true, by your logic, prints on the wall would exhibit exactly the same problem as your ones on the window after a proportionately longer time (taking into account the lower direct sunlight hours), but clearly they don't. Most of us here can point to prints which have hung for a decade or more without such issues.
-
Your own logic is defying you :-)
If the white paper reflects a lot of energy, then it can't be as hot on the "dark" side of the paper (not facing the sun) as on the "light" side of the paper (facing the sun and reflecting energy)
Given the thinness of the paper, this difference can be measured in fractions of a degree.
Furthermore, light that's *reflected*, by definition, doesn't heat the paper. Only light that's *absorbed* (e.g. by a dark surface) will heat the paper.
, furthermore, you have a very small layer of air between the paper and the glass which will be heated up and stay hot and without any direct convection won't move a lot.
There is *always* convection. The 1cm layer of air between the glass and the paper is connected to the air in the rest of the room. If it heats up, then, by definition, it will rise out of the way, allowing cooler air from beneath to take its place.
On the "dark" side you have an entire room and thus don't get a layer of air trapped.
Again, the thinness of the paper ensures that the temperature on one side is much the same as the temperature on the other.
Furthermore, the glass itself, whilst transparent, will become at least warm and again act as a thermal mass, tending to keep that side hotter.
Not when the paper isn't in direct contact with the glass.
Sure, if you hold a paper cup for a while (thinner than most media, but I guess comparable) it gets too hot to hold over time. Dip your finger into the liquid and it will burn you right away.
That's not because of the temperature of the paper - that's because of the temperature, thermal mass, density and conductivity of the water.
Liquid water stores around 4.2kJ/kg for each degree that it's heated. It's also fairly conductive and distributes heat throughout its own mass via convection. At 1g/cm2, it's also much denser than paper. If you dip your finger into hot water, your finger rapidly reaches the same temperature as the water.
Paper, on the other hand, stores much less energy and does not undergo convection. If you touch a piece of hot paper, your hand will cool down the paper much more than it will heat up your hand (since your hand, essentially, is a bag of water).
For similar reasons, you could put your arm inside the 100 million degree plasma of some types of experimental fusion reactor and suffer no thermal effects (radiation is another matter entirely).
It's true that at some part of the day, a print on the wall may receive almost as much energy as a print on the window (less that lost due to passing through the glass and the related heat into the air etc) but as you noted, the exposure time for direct sunlight will typically be far less and it has the advantage of the thermal mass of the mounting and the frame and, to a lesser degree, the air behind it and the wall. The temperature of the print is likely to be more consistent throughout the day and througout the substrate itself (i.e. less differential most of the time from one side to the other). This is important when considering expansion and contraction of different materials at different rates. More consistency, less extremes = less effect.
The expansion and contraction of paper due to fluctuations in humidity is at least an order of magnitude greater than the expansion and contraction due to temperature.
If that wasn't true, by your logic, prints on the wall would exhibit exactly the same problem as your ones on the window after a proportionately longer time (taking into account the lower direct sunlight hours), but clearly they don't. Most of us here can point to prints which have hung for a decade or more without such issues.
A decade, or even three or four decades, is insignificant for an inkjet print. I'm talking about the equivalent of 100-200 years of display.
Don't forget, high-quality microporous inkjet paper has only been around for a decade. The only long-lasting, photo-quality inkjet prints from before that were from Iris printers, which printed on uncoated paper.
-
Ummm, no. Reflected light comes back at a specific wavelength and in the process, some energy is transferred into the reflective medium.
Go ahead and test it - check the temperature on onside and the other, and note that the substrate is made of different materials on each side which will also affect it.
And 1cm between glass and paper? You had that much bluetack on it? And, no, if the gap is small enough it creates its own local environment, somewhat disconnected from the rest of the air - not entirely, but enough to produce a thermal difference.
-
Ummm, no. Reflected light comes back at a specific wavelength and in the process, some energy is transferred into the reflective medium.
Reflected light comes back at whatever wavelength the incident light was at. If it comes back at a different wavelength, it wasn't reflected - rather, it was absorbed (usually causing an electron somewhere to jump into an 'excited' state) then re-emitted as a photon of a different wavelength.
Sunlight is made up of lots of different wavelengths. A coloured object will absorb some wavelengths more than others - the average wavelength of the reflected light defines its colour. A black object absorbs all visible light wavelengths more-or-less equally. A white object reflects all visible-light wavelengths more-or-less equally. This is why white objects appear white, and heat up minimally - almost all incoming light is reflected.
Go ahead and test it - check the temperature on onside and the other, and note that the substrate is made of different materials on each side which will also affect it.
And 1cm between glass and paper? You had that much bluetack on it? And, no, if the gap is small enough it creates its own local environment, somewhat disconnected from the rest of the air - not entirely, but enough to produce a thermal difference.
How else do you use blutack if not in big blobs?
It's a 32-degree day here in Melbourne today (that's outdoor shade temperature, the usual standard of measurement). Cooler indoors. I've had two pieces of paper blutacked to the window for the past two hours - a sheet of Hahnemuhle Photo Rag Pearl and a piece of black paper from a backdrop. I've also had a sheet of white paper, matted and framed (in a small, cheap, non-conservation frame with regular glass, i.e. what you'd expect of most people) sitting on a chair well away from the window, but still receiving direct sunlight, and a similarly-framed piece of black paper next to it.
Air temperature at the back of the room, never directly illuminated by the sun: 26.5 degrees
Air temperature behind the paper: 27.2 degrees
Air temperature between the paper and the window (~1cm gap): 27.7 degrees
Temperature of the white paper (side away from the window): 29.1 degrees
Temperature of the white paper (side facing the window): 29.5 degrees
Temperature of the black paper (side away from the window): 47.6 degrees
Temperature of the black paper (side facing the window): 47.8 degrees
Temperature of the white paper in the frame: 39.7 degrees
Air temperature in the frame with white paper: 39.7 degrees
Temperature of the black paper in the frame: 58.3 degrees
Air temperature in the frame with black paper: 54.2 degrees
A lot of 'obvious' things aren't so obvious when you actually measure them.
-
So what we can discern is that there is a temperature differential and it's greater with white. The paper, despite being white, is warmer than the ambient temperature, so it's not reflecting "everything". The air trapped between the paper and the room is warmer than the room. This is in line with what I and others have suggested.
Differences in temperature don't need to be an order of magnitude to have an impact on curling, for example. The differences here of around 1-2%, particularly as there are different materials in the media, almost certainly have an affect, particularly when you expose them for 6 months over spring and summer.
There are a lot of variables and you're arbitarily attributing the results to some of them without isolating them.
Mark already made an excellent suggestion for a better test.
-
The temperature of the paper, as measured even on the hottest afternoon on the year, never exceeded 37-39 degrees and the circulation around paper Blu-Tacked to the window is much greater than any air circulation you'd have around a framed and matted print.
Besides, *any* print that is put in a location that receives direct sunlight will exceed 50 degrees at some point. ...
More than a little contradictory, no?
But still an interesting test.
Brian A
-
So what we can discern is that there is a temperature differential and it's greater with white. The paper, despite being white, is warmer than the ambient temperature, so it's not reflecting "everything". The air trapped between the paper and the room is warmer than the room. This is in line with what I and others have suggested.
Differences in temperature don't need to be an order of magnitude to have an impact on curling, for example. The differences here of around 1-2%, particularly as there are different materials in the media, almost certainly have an affect, particularly when you expose them for 6 months over spring and summer.
There are a lot of variables and you're arbitarily attributing the results to some of them without isolating them.
Mark already made an excellent suggestion for a better test.
Of course it's not reflecting everything. There's no such thing as a perfect reflector. But it's reflecting almost everything - if it weren't, it'd be a lot warmer than the ambient air temperature.
The temperature difference between the front and back of the paper is miniscule - less than 0.5 degrees. The 320gsm, coated white paper is a lot thicker than the thin, black backdrop paper, which is probably why the temperature difference between the front and the back is slightly greater for the white paper. Either way, the difference between the front and back is so small that you can safely use the temperature at the back of the paper as an analogue for the temperature at the front - it's not like there's a 5 or 10 degree difference between the two.
Regarding the air temperature, you're never going to have a perfectly-uniform temperature. But the difference between the temperature in front of the paper and the temperature behind the paper - or, indeed, the temperature at the back of the room - is only around a degree. If there were, indeed, significant air trapping there, creating a 'microclimate', the temperature there would be a lot higher - more like what you'd get in the truly enclosed spaces, such as in the frames.
Re: testing it with variable humidity/temperature without exposing to UV light - it's worth testing, but I doubt you'd see a result for decades, if not centuries. We already know that inkjet coatings are flexible when they're new and can cope with the base paper expanding and contracting with changing humidity. What we don't know is whether they can still cope with it after turning brittle (or not) with 100 years worth of UV exposure.
-
More than a little contradictory, no?
But still an interesting test.
Brian A
How is it contradictory? A piece of white paper won't get much hotter than the surrounding air temperature, since it reflects most incident light and derives its temperature largely through conduction from its surroundings.
In contrast, a printed paper gets much hotter than its surroundings when directly illuminated by sunlight, since it absorbs most of the incoming light. So a white piece of paper that reaches 39 degrees on a hot day in direct sunlight would easily reach >50 degrees if it were printed, particularly if it were printed in a dark colour.
Don't believe me? Find a white car and a black or dark blue car that have been sitting in the sun on a sunny day (easily found in any car park) and touch the bonnet of each car with the back of your hand. I can guarantee that the blue/black car will feel a lot hotter than the white car.
-
Re: testing printed, rather than unprinted paper
I suspect that printed paper would be more susceptible to cracking and peeling than non-printed paper, since porous papers are well-known for developing micro-cracks when drying after being heavily inked. These cracks can only weaken the coating.
-
I wanted to add, because I've re-read some of my posts, that I think it's good that you've done this and the discussion is very interesting and potentially useful in leading to additional tests. Apologies for coming off overly negative or harsh if I have.
I still think you're under estimating the effects of the differences that exist, btw :-)
-
Interesting thread, and quite consistent with my expectations.
I have a hierarchy in my prints from the RC (with B&W dyes) at the bottom (cheap, lots of pop, and sell well) and Arches un-coated watercolor paper with carbon pigments at the top (large size, very limited editions are of interest to collectors).
I was curious about the observation that textured inkjet matte papers may not hold up as well as the smoother ones (if I understood the comment). I talked once with an inkjet paper company rep about such things and got the impression from him that they had to back off from calendaring the paper too much. I had the impression it was due to the paper needing some "tooth" for the coating to hang onto. I had assumed this would suggest that the textured papers might actually have less problems with coatings separating, but maybe not.
Keep up the testing. (Maybe include some Arches in the next sample?)
Paul
www.PaulRoark.com
http://www.paulroark.com/BW-Info/
-
Interesting thread, and quite consistent with my expectations.
I have a hierarchy in my prints from the RC (with B&W dyes) at the bottom (cheap, lots of pop, and sell well) and Arches un-coated watercolor paper with carbon pigments at the top (large size, very limited editions are of interest to collectors).
This is why I'm trying to get Arches Hot Press working with colour, using AIS Ultramax inks in an Epson printer. These have a higher-than-normal pigment load than OEM inks (apparently 70% ink load using Ultramax inks deposits as much pigment as 100% ink load using OEM inks) to compensate for the lower ink limit on Arches. The output will presumably be similar to output from an Iris printer, but with better gamut (due to using 10 different inks in 8 different colours, instead of just CMYK like Iris). A lot of my work looks much better in colour than monochrome, so I'd like to get this working.
On the other hand, I've potentially got a very good deal on a HP Z3200 within the next two days. I'm not sure how it will perform with uncoated paper, though, even with a RIP.
I was curious about the observation that textured inkjet matte papers may not hold up as well as the smoother ones (if I understood the comment). I talked once with an inkjet paper company rep about such things and got the impression from him that they had to back off from calendaring the paper too much. I had the impression it was due to the paper needing some "tooth" for the coating to hang onto. I had assumed this would suggest that the textured papers might actually have less problems with coatings separating, but maybe not.
I didn't notice anything one way or the other re: the difference between rough papers and smooth papers. Maybe a longer test would eventually show that Canson Etching Edition or Breathing Colour Pura Velvet lasts longer than Rag Photographique or Pura Smooth. It makes sense that rough papers would hold on to coatings better than smooth papers, due to the increased surface area of the bond; however, textured papers have their own problems in that they're incredibly fragile and vulnerable to surface damage, even after spraying.
Keep up the testing. (Maybe include some Arches in the next sample?)
Paul
www.PaulRoark.com
http://www.paulroark.com/BW-Info/
There's no point testing uncoated Arches when you're trying to test the long-term stability of a coating - there's literally nothing there to test!
-
On the other hand, I've potentially got a very good deal on a HP Z3200 within the next two days. I'm not sure how it will perform with uncoated paper, though, even with a RIP.
On good quality offset papers with little coating the Z3200 does a good job, not delivering the same gamut as possible on inkjet coated papers but better than what I experienced with other inkjet inks in the past. Paul has more experience with HP B&W inks on Arches art papers etc.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
-
On good quality offset papers with little coating the Z3200 does a good job, not delivering the same gamut as possible on inkjet coated papers but better than what I experienced with other inkjet inks in the past. Paul has more experience with HP B&W inks on Arches art papers etc.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
Thanks. How does the gamut compare to Iris prints?
Also, what do you mean by 'little' coating. Isn't it either coated or uncoated? I'm looking at watercolour papers, specifically Arches Hot Press. Or have you found a better option?
-
Quality offset papers have a light coating or similar improvements to achieve better print quality than possible on uncoated offset papers. There is a diffuse boundary between uncoated and coated papers if you count all the methods to get a smoother surface for printing: sizing methods, hot press satinizing, twin papers like Mellotex where the sieve sides of two thin papers interlock to create a thicker paper with no sieve sides, plate finished on both sides then. The paper I print on BioTop 3 belongs to uncoated in the catalogs but for me uncoated is more like what we call Roman here and what you will find in older cheap pocket books made in letterpress. Biotop paper qualities improved for web inkjet printing exist too, mainly dye inks are used in that industry and the paper made suitable for them and that fast printing process. Other big paper mills have similar qualities ready for that industry, hard to get for small shops; jumbo rolls. "infusion" you came across already, the surface polarity can be made suitable too for a specific printing process like inkjet.
The Arches qualities Paul uses are better compared to the uncoated Roman paper quality I referred to, though within the range of Arches papers the base sizing, surface sizing and surface treatment can be different for different print processes like intaglio, lithography, silkscreen, woodcut. The papers used for the Iris were taken from that range and had to cope with dye inks. The gamut of dye inks can be better on uncoated papers as there is little (inkjet head) penalty on increasing the colorant amount in dye inks. Color constancy, bleed, wet resistance, migration, light and gas fading are however way worse than what we have now in pigment inkjet inks. A fresh Iris print (no longer made) on Arches will probably be better in gamut than what I can make on that Biotop with my Z3200. The worst Iris prints considering longevity were actually made with Lyson Iris dye inks on Lyson rebranded Hahnemühle (German Etching for example) papers with an inkjet coating. Papers chosen because they delivered a better image resolution and gamut than the "uncoated" Arches papers.
Be prepared for a compromise in whatever you aim for.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
-
Quality offset papers have a light coating or similar improvements to achieve better print quality than possible on uncoated offset papers. There is a diffuse boundary between uncoated and coated papers if you count all the methods to get a smoother surface for printing: sizing methods, hot press satinizing, twin papers like Mellotex where the sieve sides of two thin papers interlock to create a thicker paper with no sieve sides, plate finished on both sides then. The paper I print on BioTop 3 belongs to uncoated in the catalogs but for me uncoated is more like what we call Roman here and what you will find in older cheap pocket books made in letterpress. Biotop paper qualities improved for web inkjet printing exist too, mainly dye inks are used in that industry and the paper made suitable for them and that fast printing process. Other big paper mills have similar qualities ready for that industry, hard to get for small shops; jumbo rolls. "infusion" you came across already, the surface polarity can be made suitable too for a specific printing process like inkjet.
I took a look at Biotop 3 - it seems to be similar to what HP does with its ColorLok technology. I'd consider it uncoated, in the sense that there's no separate inkjet coating on top of the paper that can come unstuck with time. Unfortunately, all these papers seem to be fairly low-weight and low-grade compared to the 300-400gsm 100% cotton papers from Hahnemuhle and others, as well as the Japanese, Nepali and Indian handmade papers, that we commonly use in fine art and photography.
I really liked Hawk Mountain's Red Tail - I wish they still made it, or someone else made something like it. A heavy watercolour paper with Colorlok or similar technology (instead of an inkjet coating) would be nice, too.
The Arches qualities Paul uses are better compared to the uncoated Roman paper quality I referred to, though within the range of Arches papers the base sizing, surface sizing and surface treatment can be different for different print processes like intaglio, lithography, silkscreen, woodcut. The papers used for the Iris were taken from that range and had to cope with dye inks. The gamut of dye inks can be better on uncoated papers as there is little (inkjet head) penalty on increasing the colorant amount in dye inks. Color constancy, bleed, wet resistance, migration, light and gas fading are however way worse than what we have now in pigment inkjet inks. A fresh Iris print (no longer made) on Arches will probably be better in gamut than what I can make on that Biotop with my Z3200.
I was worried that would be the case, despite Iris only being a four-ink process.
I guess that's why I'm trying to have as wide a 'baseline' gamut as possible, in order to still be left with a wide gamut after imposing the ink limits for uncoated paper.
The worst Iris prints considering longevity were actually made with Lyson Iris dye inks on Lyson rebranded Hahnemühle (German Etching for example) papers with an inkjet coating. Papers chosen because they delivered a better image resolution and gamut than the "uncoated" Arches papers.
Not surprising, given that they're dye inks on porous paper.
I wonder if results would have been better using swellable paper rather than microporous.
Be prepared for a compromise in whatever you aim for.
I'm expecting to have to compromise gamut, but hope to be able to achieve somewhere near the gamut of coated matte papers. After all, you can get a Dmax of 1.60-1.65 on Arches (similar to many matte papers) and can push it up even further by heating the paper and increasing the ink load.
I had one of my prints made on Arches by Paul - it turned out very well. So, for black-and-white prints, I'm experimenting with a combination of MIS pure carbon pigments and Cone Piezography pigments, in order to produce a print that runs from neutral to slightly cool (depending on the lighting) in the shadows, to slightly warm in the highlights (a bit like split-toned selenium/sepia prints). But black-and-white prints on uncoated paper are a lot simpler, since you don't have to worry about ink lightfastness (carbon pigment being more-or-less permanent) or colour gamut, and you can easily do it on an old, second-hand seven- or eight-ink 9600 or 9800, whereas, for colour, you'd want a ten-ink 9900.
It'd be really nice to find a type of coated paper that remains supple, flexes with the paper and won't peel, crack or disintegrate over time. 'Infused' inkjet coatings certainly fit the bill (there being no layer to separate from the paper) - but I can't find anyone who makes one at the moment (although they sell infused, uncoated canvas). Stable coatings are certainly possible - after all, we have egg tempera paintings on wood dating from the early days of the Roman Empire. If one of these types of coated paper turns out to be stable, I wouldn't have to go through all this experimentation and accept a compromised gamut to produce highly-conservable premium-edition prints!
Do you have any photos of your Biotop/Z3200 prints that you can post, so I can see what sort of gamut you're getting?
-
For best longevity, the only neutralized carbon (that is, carbon cooled with color pigments) I trust is HP's Z3200 PK, and grays. The light grays are cooler than the PK diluted with the generic base. Take a look at the graph on the top of page 11 of http://www.paulroark.com/BW-Info/7800-EbHP-2013.pdf to see how neutral a print made with 50% Eboni-6 (100% carbon) and 50% HP Z3200 PK, diluted with generic base can be. With a Lab B rise of only one unit over the paper base, it looks dead neutral. If the OEM dilutions of the HP grays had been used it would be even cooler. But a one unit Lab B rise is virtually undetectable.
Paul
www.PaulRoark.com
-
I really liked Hawk Mountain's Red Tail - I wish they still made it, or someone else made something like it.
Yup, I really saw something special in Red Tail, too, but I was involved in the R&D on that paper, so I have a personal bias. Because a paper mill has to commit a full production run to doing an infusion trial (it's difficult to create the same properties on a smaller pilot line), the project was an expensive R&D effort. Developing a high quality infused paper is unlike developing new coating technologies where you can split off sections of the base paper run and do multiple coating trials to perfect the results. Lastly, printmakers like yourself, Paul and Ernst, indeed several of you who participate in the Lula Printers and Printing forum, represent about the 0.001 percentile of printmakers out there with your genuine interest and concern with longevity. You want to push the envelope and not take a "good is good enough" attitude towards the subject of print print quality and recognize that print permanence is also a fundamental property of a high quality print. I share those concerns, but from my perspective I don't feel we are main stream enough in our thinking or product expectations that we influence the "industry influencers" to any significant extent.
Anyway, Red Tail represented the last trial effort with the infusion project at that particular paper mill. Hawk Mountain made a sweet deal to acquire that last lot and then convert it so that it could attempt to market it, Thus, this infused paper briefly entered the market as Red Tail, but not in time to help save Hawk Mountain which it probably wouldn't have anyway. There are too many suppliers out there right now (Ilford is the latest casualty). We will see more consolidation because the fine art printing and photographic printing market just isn't very big or growing as fast as it once was. I guess we can thank smartphones, tablets, and Facebook for the rapid decline in photographic printing >:( That said, if I was a technical manager at one of the key media suppliers to the fine art digital printing market who will need to depend on retaining and gaining market share in this crowded market, I'd be looking at all these issues we've been discussing with a real R&D interest in finding more and more innovative ways to improve the product line.
From a technical perspective, Red Tail came close but still fell a little short on color gamut and dmax compared to the latest coated inkjet papers. However, most printmakers choose primarily on color gamut and image "pop", so the fact that Red Tail didn't excel in those factors was an understandable reason why the paper company management abandoned the effort even though that paper has other subtle and yes unique properties (e.g. fantastic lay-flat and double-sided printing properties ideal for book binding projects).
All that said, there was one last R&D trial I wanted to run, and I genuinely believe that it would have gotten the color and density range at least to the point of meeting if not exceeding in color gamut and dmax, but by the time I"d gathered that technical insight, it was tool late to convince the paper mill's management to make one last effort. Such is the reality of being a technical guy rather than a marketing guy. Everyone of course, has to be on the same page, but marketing and accounting concerns always tend to trump R&D budgets unless the science and engineering appears to be headed in a rosy straight-line path. With truly innovative R&D a straight-line path to success is rarely the case.
best,
Mark
http://www.aardenburg-imaging.com
-
For best longevity, the only neutralized carbon (that is, carbon cooled with color pigments) I trust is HP's Z3200 PK, and grays. The light grays are cooler than the PK diluted with the generic base. Take a look at the graph on the top of page 11 of http://www.paulroark.com/BW-Info/7800-EbHP-2013.pdf to see how neutral a print made with 50% Eboni-6 (100% carbon) and 50% HP Z3200 PK, diluted with generic base can be. With a Lab B rise of only one unit over the paper base, it looks dead neutral. If the OEM dilutions of the HP grays had been used it would be even cooler. But a one unit Lab B rise is virtually undetectable.
Paul
www.PaulRoark.com
I guess that's the beauty of printing on Arches Hot Press Natural - since the paper base is warm, 100% carbon MIS inks actually look cool against it! Not *really* cool, but cool enough to be used as the 'cool' end of a 'split-tone' carbon inkset (with Cone inks forming the lighter/less dense end of the spectrum).
-
Yup, I really saw something special in Red Tail, too, but I was involved in the R&D on that paper, so I have a personal bias. Because a paper mill has to commit a full production run to doing an infusion trial (it's difficult to create the same properties on a smaller pilot line), the project was an expensive R&D effort. Developing a high quality infused paper is unlike developing new coating technologies where you can split off sections of the base paper run and do multiple coating trials to perfect the results. Lastly, printmakers like yourself, Paul and Ernst, indeed several of you who participate in the Lula Printers and Printing forum, represent about the 0.001 percentile of printmakers out there with your genuine interest and concern with longevity. You want to push the envelope and not take a "good is good enough" attitude towards the subject of print print quality and recognize that print permanence is also a fundamental property of a high quality print. I share those concerns, but from my perspective I don't feel we are main stream enough in our thinking or product expectations that we influence the "industry influencers" to any significant extent.
Anyway, Red Tail represented the last trial effort with the infusion project at that particular paper mill. Hawk Mountain made a sweet deal to acquire that last lot and then convert it so that it could attempt to market it, Thus, this infused paper briefly entered the market as Red Tail, but not in time to help save Hawk Mountain which it probably wouldn't have anyway. There are too many suppliers out there right now (Ilford is the latest casualty). We will see more consolidation because the fine art printing and photographic printing market just isn't very big or growing as fast as it once was. I guess we can thank smartphones, tablets, and Facebook for the rapid decline in photographic printing >:( That said, if I was a technical manager at one of the key media suppliers to the fine art digital printing market who will need to depend on retaining and gaining market share in this crowded market, I'd be looking at all these issues we've been discussing with a real R&D interest in finding more and more innovative ways to improve the product line.
From a technical perspective, Red Tail came close but still fell a little short on color gamut and dmax compared to the latest coated inkjet papers. However, most printmakers choose primarily on color gamut and image "pop", so the fact that Red Tail didn't excel in those factors was an understandable reason why the paper company management abandoned the effort even though that paper has other subtle and yes unique properties (e.g. fantastic lay-flat and double-sided printing properties ideal for book binding projects).
All that said, there was one last R&D trial I wanted to run, and I genuinely believe that it would have gotten the color and density range at least to the point of meeting if not exceeding in color gamut and dmax, but by the time I"d gathered that technical insight, it was tool late to convince the paper mill's management to make one last effort. Such is the reality of being a technical guy rather than a marketing guy. Everyone of course, has to be on the same page, but marketing and accounting concerns always tend to trump R&D budgets unless the science and engineering appears to be headed in a rosy straight-line path. With truly innovative R&D a straight-line path to success is rarely the case.
best,
Mark
http://www.aardenburg-imaging.com
A huge pity, really.
I would have thought something like Red Tail, or another infused paper, would be something a small paper company could really use to carve a niche for themselves, offering something that no-one else can. Not something I would expect from Hahnemuhle or Canson, but something for a small, independent player to carve itself a place in the market that the big players don't cover. Even a fine-art-quality cotton rag paper treated with HP's Colorlok or similar technology would be nice. After all, it's not as if even 'standard' matte papers like Hahnemuhle Photo Rag have huge Dmax or colour gamut - yet people still use them despite the 'pop'.
And the really major application wouldn't even be in photography or art - it would be in the preservation of important documents. Diplomas, signed contracts, treaties, historical documents, etc.
Kernow make several lines of infused, unprimed canvas (its Kernewek fabrics), but, as far as I know, no-one does the same for paper, apart from a few small sheets by Bockingford with poor test results.
Is the infusion process something that could be done by a small, independent paper maker (e.g. the kind that makes handmade artisan papers)? As in, does it use off-the-shelf inkjet coatings (similar to InkjetAid) applied in a different way, or is it a completely different substance? If it's something that can be done by any paper maker using off-the-shelf materials, it might be worth having such a paper maker produce a small batch as a trial run, and using it as a standard paper if it turns out well.
-
[... I guess that's the beauty of printing on Arches Hot Press Natural - since the paper base is warm, 100% carbon MIS inks actually look cool against it! ...
[/quote]
That is part of it. Also the un-coated papers usually print more neutrally than coated ones. There is something about the coating that warms carbon. A minority of coated matte papers can come close. I don't know enough about the process to know what the variables are, but I note the papers in my PDFs that are more "carbon friendly" in terms of having a low paper-base to peak-warmth differential. Epson Hot Press Natural is one of them.
Visually, if the image is on the wall and isolated from brightened paper, the eye seems to do, in effect, a white balance on the paper base or mat board. If that is the white point in the visual field, then how warm the image appears seems to be determined largely by the change in the Lab B from this paper base or matte board to the light and medium tones in the image.
Paul
www.PaulRoark.com
-
And the really major player wouldn't even be in photography or art - it would be in the preservation of important documents. Diplomas, signed contracts, treaties, historical documents, etc.
And what major players might that be? Museums and Archives are largely clueless about the new technologies. They tend to wait until modern stuff becomes an historic medium that they are then obligated to collect and understand.
Moreover, the overriding sentiment for experts in document and photo conservation is to rely on "proven" technologies that have existed for a long time, so a modern infused product would not pass that litmus test. I even see that sentiment expressed in this thread, with traditionally sized "uncoated" papers like Arches ColdPress getting the nod as far superior.
Few folks understand, for example, that "traditional" cotton papers aren't made the same way they were 100 years ago even though the marketing folks would have you believe the whole "we've been making this for 400 years" mystique. Does anyone really think 100% cotton means the product is 100% cotton? It just means the linters going into the mixing vat might be 100% cotton. But paper contains many chemical additives. Traditional sizing agents like gelatin and starch, etc. have given way to more modern internal sizing agents like AKD, and modern optical brighteners are more of the norm than the exception. Just sayin... empirical knowledge of traditional media stability over time is extremely useful as is modern laboratory testing to determine modern durability issues. How many media vendors pay attention to all these long term durability issues if the product they make looks good on day one and is being praised by the consumer as the latest and greatest? That's where the enduser community has to demand more transparency on durability factors, and especially in this modern digital era (and throw-away society) I don't think we've done that as well as we could.
best,
Mark
-
And what major players might that be? Museums and Archives are largely clueless about the new technologies. They tend to wait until modern stuff becomes an historic medium that they are then obligated to collect and understand.
Which is a very poor way of doing it. Much better to work out how to print something that will stand the test of time, than to not look into it and, forty years later, struggle to find a way to save important images and artworks which are fading or falling apart.
Moreover, the overriding sentiment for experts in document and photo conservation is to rely on "proven" technologies that have existed for a long time, so a modern infused product would not pass that litmus test.
But the only 'proof' we have is that existing technologies for digital printing aren't very durable. Silver-gelatin fades rapidly compared to inkjet. Toner from laser printers and photocopiers falls off the paper. Inkjet is a very promising technology in terms of durability of the image and an increasingly important means of photographic output, displacing chromagenic prints - yet they haven't cared to test the durability of the material it's printed on!
I even see that sentiment expressed in this thread, with traditionally sized "uncoated" papers like Arches ColdPress getting the nod as far superior.
I wouldn't say it's superior - just that nothing else has been tested for anything other than lightfastness and anything with a coating layered on top of it (as opposed to impregnated within it) has an obvious weakness that could lead to its premature breakdown, well before the inks fade.
Few folks understand, for example, that "traditional" cotton papers aren't made the same way they were 100 years ago even though the marketing folks would have you believe the whole "we've been making this for 400 years" mystique. Does anyone really think 100% cotton means the product is 100% cotton? It just means the linters going into the mixing vat might be 100% cotton. But paper contains many chemical additives. Traditional sizing agents like gelatin and starch, etc. have given way to more modern internal sizing agents like AKD, and modern optical brighteners are more of the norm than the exception. Just sayin... empirical knowledge of traditional media stability over time is extremely useful as is modern laboratory testing to determine modern durability issues. How many media vendors pay attention to all these long term durability issues if the product they make looks good on day one and is being praised by the consumer as the latest and greatest? That's where the enduser community has to demand more transparency on durability factors, and especially in this modern digital era (and throw-away society) I don't think we've done that as well as we could.
The rise in advertising and flashy, attention-grabbing, throwaway magazines over the past fifty or sixty years has a lot to answer for in that regard - printing has become more driven by short-term commercial applications than long-term storage of information. Books from 1800 hold up a lot better than books from 1950.
And the general public (most of whom are consumers of photos) haven't even thought about it at all. Case in point - have you seen a photo of your great-grandmother as a child? Quite possibly - if she had her photo taken, it was probably as a platinum print. What about your grandmother? Very likely, too - it was probably a silver-gelatin print, toned to completion with sepia, selenium or gold, with minimal fading (untoned prints would have exhibited significant fading). What about photos of your mother as a child? Probably not too many - most of these are likely to be colour chromogenic prints and would have faded significantly since then. And what about your own childhood photos? These are probably colour chromogenic prints made on RC paper and deteriorate significantly after just 20-30 years. Given how much your photos, and those of your mother, have deteriorated, how do you think they'll look in 50-100 years' time? Your grandchildren will probably still have photos of your grandmother and great-grandmother, but those of you and your mother would have long since faded or disintegrated. But most people haven't had it put to them like that.
-
And the general public (most of whom are consumers of photos) haven't even thought about it at all. Case in point - have you seen a photo of your great-grandmother as a child? Quite possibly - if she had her photo taken, it was probably as a platinum print. What about your grandmother? Very likely, too - it was probably a silver-gelatin print, toned to completion with sepia, selenium or gold, with minimal fading (untoned prints would have exhibited significant fading). What about photos of your mother as a child? Probably not too many - most of these are likely to be colour chromogenic prints and would have faded significantly since then. And what about your own childhood photos? These are probably colour chromogenic prints made on RC paper and deteriorate significantly after just 20-30 years. Given how much your photos, and those of your mother, have deteriorated, how do you think they'll look in 50-100 years' time? Your grandchildren will probably still have photos of your grandmother and great-grandmother, but those of you and your mother would have long since faded or disintegrated. But most people haven't had it put to them like that.
Preaching to the Choir :) But the Chapel is small, and few folks are in attendance ;) Sorry to sound cynical. I wouldn't do what I'm doing if the apparent cynicism overwhelmed me. Van Gogh comes to mind. He didn't sell a single painting in his lifetime (except to his brother who wanted to support him) and unlike me he got frustrated enough to cut off his own ear, and questionable history has it recorded that he eventually took his own life. Nonetheless, he believed passionately in his own work and kept doing it when the financial aspects of the matter indicated clearly he should pursue something else. I do wish he'd spent a little more effort evaluating the color pigments he chose. A few important ones in his palette weren't very light fast ;)
-
There's no 'close range' when it comes to sunlight. It all comes from the same source 150 million kilometres away. If an object is receiving direct sunlight, it makes no difference whether it's 1cm away from the glass or 10m behind it.
In a vacuum, yes. In an environmentally controlled room, no. And attached to the glass definitely not. I don’t think any of these papers were designed for sustained exposures in the 40c range. That much heat is hard on anything, especially with no circulation.
As I said, interesting and I applaud the effort because I think we are all concerned with the long term stability and durability of inkjet papers and their receptor coats, but I don’t think there is a scientific test that can be applied short term to extrapolate long term affects. There just isn’t any way to accelerate an aging test for this type of deterioration by exaggerating the conditions.
One other thought, seems like the test you made would also most likely have faded the images beyond use, so whether the paper makes it or not might not matter because the image wouldn’t make it.
-
... but I don’t think there is a scientific test that can be applied short term to extrapolate long term affects. There just isn’t any way to accelerate an aging test for this type of deterioration by exaggerating the conditions.
Actually there is. One needs to collect material properties like humidity and temperature coefficients of expansion for each of the component layers, plus the stress and strain-to-break limits, and the thicknesses of each layer which can all be done in a laboratory if one has access to the materials. Then input the data into a computer model using an analytical tool called finite element analysis well known to mechanical engineers, and one can predict the elastic-plastic deformation problems that will occur in the finished piece pretty darn well. This approach to the problem was the subject of research I participated in over twenty years ago with my colleagues Drs. Mecklenburg, Tumosa, and Erhardt at the Smithsonian Institution. It's a subject near and dear to my heart, but regrettably takes some equipment I don't have at Aardenburg Imaging & Archives, otherwise I'd be pursuing this issue on a much more rigorous level.
The work was quite controversial at the time because the results of our research eventually called into question the need for highly "flat-lined" environments (i.e. very precise and expensive control of temperature and humidity in the storage and display areas) which was the consensus thinking at the time in the Museum and Archives community. Our findings did not suggest one could be cavalier with regard to controlling the indoor climate as the critics claimed we were advocating , but one could indeed loosen the tolerances safely to wider than ±2F and ± 2%RH that was being recommended by most conservators at the time, up to ± 15%RH on the humidity range and in some cases very wide on temperature. It was the safe and allowable temperature range I was particularly interested in for the Smithsonian's incredible photographic collections because one could not pursue cold storage of photographic collections without proof that this amazing conservation procedure was physically safe for the collection materials.
The current trends towards a "greener" more "sustainable" and hence affordable indoor climate control policy in the museum and archives community has brought about a revisitation of our research findings in these modern times, and oddly enough, our early research on this subject is much more favorably regarded (and vindicated as well) in today's museum and archives community :)
cheers,
Mark
http://www.aardenburg-imaging.com
-
In a vacuum, yes. In an environmentally controlled room, no.
I suggest that you go and actually measure the light level in a sunlit room, firstly next to the window, then on the opposite side of the room (but still receiving direct sunlight through the window). You'll find that the incident light level is identical. Do some actual experimentation instead of criticising without results or a scientifically-defensible theory to back it up. 'It feels hotter' or 'it looks brighter' doesn't actually mean that it is.
Conjecture and 'what it feels like' are often not consistent with what you find when you actually mention things. It feels a lot hotter next to a window with sunlight streaming in, than on the opposite side of the room away from the sun. The air temperature, when you measure it, will be more-or-less identical. It only feels hotter because you're getting warmed by radiant heat from the sun. But the paper, being near-white, barely gets heated (printed paper is a different story altogether).
And attached to the glass definitely not.
So, a sample receives stronger UV light just because it's attached to the glass rather than 3m behind the glass? Inverse square law says not - not when the source of light is 150 million kilometres away.
I don’t think any of these papers were designed for sustained exposures in the 40c range. That much heat is hard on anything, especially with no circulation.
In other words, you're saying that these papers aren't designed to be framed. A frame has less air circulation than anything else, and gets much hotter than unframed paper, even with short (1-2 hours) periods of direct sunlight.
One other thought, seems like the test you made would also most likely have faded the images beyond use, so whether the paper makes it or not might not matter because the image wouldn’t make it.
Light exposure during a six-month period would have been well under 100 Mlux hours, most likely around 50 Mlux hours. That wouldn't have been enough to significantly fade any of the inkjet prints. Images are useful for significantly longer than the times listed on Aardenburg - those exposure levels are for when fading first becomes visible, not for when the images become useless.
-
Actually there is. One needs to collect material properties like humidity and temperature coefficients of expansion for each of the component layers, plus the stress and strain-to-break limits, and the thicknesses of each layer which can all be done in a laboratory if one has access to the materials. Then input the data into a computer model using an analytical tool called finite element analysis well known to mechanical engineers, and one can predict the elastic-plastic deformation problems that will occur in the finished piece pretty darn well. This approach to the problem was the subject of research I participated in over twenty years ago with my colleagues Drs. Mecklenburg, Tumosa, and Erhardt at the Smithsonian Institution. It's a subject near and dear to my heart, but regrettably takes some equipment I don't have at Aardenburg Imaging & Archives, otherwise I'd be pursuing this issue on a much more rigorous level.
The work was quite controversial at the time because the results of our research eventually called into question the need for highly "flat-lined" environments (i.e. very precise and expensive control of temperature and humidity in the storage and display areas) which was the consensus thinking at the time in the Museum and Archives community. Our findings did not suggest one could be cavalier with regard to controlling the indoor climate as the critics claimed we were advocating , but one could indeed loosen the tolerances safely to wider than ±2F and ± 2%RH that was being recommended by most conservators at the time, up to ± 15%RH on the humidity range and in some cases very wide on temperature. It was the safe and allowable temperature range I was particularly interested in for the Smithsonian's incredible photographic collections because one could not pursue cold storage of photographic collections without proof that this amazing conservation procedure was physically safe for the collection materials.
The current trends towards a "greener" more "sustainable" and hence affordable indoor climate control policy in the museum and archives community has brought about a revisitation of our research findings in these modern times, and oddly enough, our early research on this subject is much more favorably regarded (and vindicated as well) in today's museum and archives community :)
cheers,
Mark
http://www.aardenburg-imaging.com
Of course, stress and elastic limits change with time, as coatings are exposed to UV light and atmospheric pollutants - something that a fresh piece of paper can withstand may be too much for a 50-year-old piece of paper. Hence the need for accelerated ageing tests, to age these coatings to the equivalent of hundreds of years of normal display.
I guess I'm not so concerned with the means and methods conservators use, but how to produce a print that will stand the test of time outside of a controlled or museum environment. Most of my prints don't go to carefully-stored archives. They go to homes everywhere from deserts to the humid tropics, to centuries-old temples with no climate control, to displayed collections in desert forts and damp, musty wineries. They're looked after by people who wouldn't know the slightest thing about paper and printing, not curators who have studied it their whole lives. I'd like to make prints that will stand up to real-world conditions, not just in carefully-controlled archives and libraries.
-
Of course, stress and elastic limits change with time, as coatings are exposed to UV light and atmospheric pollutants - something that a fresh piece of paper can withstand may be too much for a 50-year-old piece of paper. Hence the need for accelerated ageing tests, to age these coatings to the equivalent of hundreds of years of normal display.
Correct, and can be done in the lab and input into the model. Been there, done that.
This is my last post on Lula for a while, friends. I want to go make some prints and do some photography!!!
cheers, mark
P.S. thank you Shadowblade et al, for a stimulating discussion.
-
I suggest that you go and actually measure the light level in a sunlit room, firstly next to the window, then on the opposite side of the room (but still receiving direct sunlight through the window). You'll find that the incident light level is identical. Do some actual experimentation instead of criticising without results or a scientifically-defensible theory to back it up. 'It feels hotter' or 'it looks brighter' doesn't actually mean that it is.
but I'm not (and have never been) referring to the amount of light. Most of the degradation you describe was not caused by the light, but by the thermal conditions of the test.
I guess I could get a thermometer of some type and test the temperature of the two conditions pretty easily, but considering it's a piece of white paper I don't think it would even get warm across the room. But then again, I'm having trouble with my motivation, because I can't see any relevant conclusions to your non scientific test that are applicable to conditions normally experienced by images on a wall in a room. I think Mark mentioned how extremely difficult it is to to accelerated testing on this stuff, and we all know that storing prints in a warm environment for extend lengths of time is bad on them, nothing new there.
Anyway, enough for me ...
good luck with whatever you are trying to figure out ...
-
FWIW, you don't get the same amount of sunlight (direct or otherwise) on a print on the window as you do one back on the wall. On the window, the maxium amount of light is available and striking it. In the room, that light is filling the entire room, not just landing on that one surface, so the exposure must be less, even when "direct". Some of it will reflect of other surfaces and may eventually make it to the print, but it will still be less.
-
FWIW, you don't get the same amount of sunlight (direct or otherwise) on a print on the window as you do one back on the wall. On the window, the maxium amount of light is available and striking it. In the room, that light is filling the entire room, not just landing on that one surface, so the exposure must be less, even when "direct". Some of it will reflect of other surfaces and may eventually make it to the print, but it will still be less.
Once again, completely not true.
Light enters through the whole window, not just the part of the window covered by the print. The amount of light hitting the print depends entirely on the intensity of the incoming light, measured in lux. Since the point source of light is hundreds of millions of kilometres away, the difference in intensity of light from one end of the room to the other (a few metres) is negligible - the intensity of direct sunlight at the window will be the same as the the intensity of direct sunlight at the back of the room. Just that an object near the window will be subject to direct sunlight for a longer period of time each day than an object at the back of the room.
If you don't believe me, measure it yourself.
-
but I'm not (and have never been) referring to the amount of light. Most of the degradation you describe was not caused by the light, but by the thermal conditions of the test.
You keep harping on about the 'thermal conditions' the print is exposed to, but haven't even accounted for the fact that a framed print, due to being stored in what's essentially a tiny, enclosed space with zero air circulation, gets a *lot* hotter with even a brief exposure to direct sunlight than an unframed print sitting in the same direct sunlight all day. And a printed piece of paper gets a lot hotter than a unprinted piece of the same paper, since it absorbs a lot more solar radiation. A white object derives its temperature largely from the air temperature around it, since most radiant heat/light is reflected rather than absorbed. And there will be next to no difference in air temperature from one side of a room to the other.
Moreover, it's been established that dimensional changes in paper caused by changes in humidity are at least an order of magnitude greater than changes caused by temperature. Compared to what humidity does to paper, the effect of temperature is insignificant. When you're doing a qualitative, rather than quantitative test (e.g. working out which paper breaks down first, rather than exactly how much exposure is needed for an individual paper to break down) the effects of temperature are further neutralised, since every sample is being put through the same conditions.
And a basic knowledge of chemistry will tell you that, unless you're melting something or denaturing proteins, temperature doesn't *cause* breakdown. It merely accelerates it, like it accelerates any other chemical reaction.
I guess I could get a thermometer of some type and test the temperature of the two conditions pretty easily, but considering it's a piece of white paper I don't think it would even get warm across the room. But then again, I'm having trouble with my motivation, because I can't see any relevant conclusions to your non scientific test that are not applicable to conditions normally experienced by images on a wall in a room.
Exactly - it won't get warm across the room, and it won't get warm next to the window either. Being a white object, it will stay near the ambient air temperature.
Why don't you get a printed image (any printed image will do), put it in a frame with a mat board and a thermometer and put it in direct sunlight in summer for even a few minutes, and see what the air temperature in the frame is? Then you'll see how a framed print gets much, much hotter than an unframed piece of white paper in a very short period of time, making temperatures of 40-45 degrees seem cool in comparison. After all, even an enclosed space as large as a car gets extremely hot in a few minutes. The frame is many times smaller and has a huge radiation collecting surface area (the print area) compared to the volume of air within it.
I think Mark mentioned how extremely difficult it is to to accelerated testing on this stuff, and we all know that storing prints in a warm environment for extend lengths of time is bad on them, nothing new there.
Anyway, enough for me ...
good luck with whatever you are trying to figure out ...
Of course storing prints in a warm environment is bad for them. That's why it's worth testing. Because, outside of archives and well-maintained collections, prints put on display are subject to everything from freezing winter temperatures, to hot, dry conditions, to fumes from cooking, to cigarette smoke, to 100% humidity. If you want prints that will last in a real-world environment, not just when carefully maintained in a collection by conservation experts, you need to print on material that can withstand all these conditions.
***
Essentially, what you're saying is that the results are irrelevant, since you believe that no print normally displayed (in a home, shop or wherever) would be subject to the temperatures experienced by the paper in the test.
To back up your argument and make it more than conjecture, what you'd need to do is take a framed, matted, printed piece of paper, expose it to direct sunlight for 15, 30 or 60 minutes on a hot day and measure the surface temperature of the print as well as the air temperature within the frame. If it doesn't get much hotter than ambient air temperature, then your argument has merit. But what you'll find is that the temperature in the frame and on the printed paper will get a *lot* hotter than ambient air temperature, and hotter than anything experienced by the papers in my test.
You need to stop passing off opinion as 'fact' and actually provide some evidence refuting the test results or conditions - measured temperatures or light levels showing huge differences in light or temperature from one end of the room to the other, or measurements of temperatures in frames - or an argument you can back up with established scientific theory (e.g. differences in illumination from one end of the room to the other, backed up by the inverse square law). Otherwise everything you're saying is pretty much conjecture, with no basis in fact other than you not liking the results.
-
All we've been saying, really, and continue to say, is that the input variables are numerous and you have not isolated them for your results. You are presenting results and then drawing conclusions. It's little different to speculation when you have no way of falsifying the results you're presenting.
You also dismissed the results that confirmed what I had been saying about temperature differentials - your results exactly confirmed the variations that I predicted. You say the differences are too small to matter, but you haven't tested anything to verify that.
It's a good subject and a good test, but your results are not comprehensive - there's room for more testing, not least of which is to isolate the various factors that could be contributing to try to determine what it is that's actually causing the issue, rather than assuming the answer.
-
All we've been saying, really, and continue to say, is that the input variables are numerous and you have not isolated them for your results. You are presenting results and then drawing conclusions. It's little different to speculation when you have no way of falsifying the results you're presenting.
You also dismissed the results that confirmed what I had been saying about temperature differentials - your results exactly confirmed the variations that I predicted. You say the differences are too small to matter, but you haven't tested anything to verify that.
It's a good subject and a good test, but your results are not comprehensive - there's room for more testing, not least of which is to isolate the various factors that could be contributing to try to determine what it is that's actually causing the issue, rather than assuming the answer.
Quite the opposite, really.
Long-established knowledge gives us the following facts as a starting point:
1. That paper is a hygroscopic material, and that a sheet of paper changes its dimensions significantly as the relative humidity of the surrounding air changes.
2. That the coefficient of thermal expansion of paper, taken as a whole sheet, is extremely low - less than glass, metal, concrete, plastics of all kinds and even graphite. Part of this is due to the porous nature of paper - individual fibres may expand (although the coefficient of thermal expansion even of individual fibres is very low in the longitudinal direction, and still fairly low across the fibre) but, when they expand, they simply fill the gaps between the fibres, rather than causing the sheet of paper to expand as a whole.
3. That the major source of stress at an interface between two layers made of different materials is the difference in dimensional change between the two materials when exposed to the same environmental conditions. This is regardless of what the two materials are - paper and coating, copper and zinc, concrete and steel.
4. That the response of the individual layers to stress at the interface depends on the Young's modulus and yield points (elastic limit and fracture point) of the material, as well as the strength of the bond between the two materials.
5. That exposure to ultraviolet light and atmospheric pollutants can alter the physical characteristics of a material, particularly a material based on organic molecules.
From your arguments, you obviously disagree with point (2), but the results of my second experiment demonstrate that point 2 isn't even relevant when considering the results of the first experiment.
From these principles, we can infer the following hypotheses:
1. That the Young's modulus and yield points of a material (in this case, the inkjet coating) can change as the material is altered on exposure to ultraviolet light and atmospheric pollutants. Therefore, a stress that doesn't affect a new coating (e.g. reducing the RH to 10%) could possibly cause failure in a coating whose stress-strain characteristics have been altered by UV light and pollutants.
2. That failure of a coating material can occur either within the coating material itself (cracking, buckling and disintegration) due to the stress in the material exceeding the yield points of the material, or at the junction between the coating material and the substrate (delamination and 'flaking'), due to failure of the bond between the two materials.
3. That the vast majority of dimensional change in paper is due to hygroscopic effects rather than thermal expansion.
Obviously, you disagree with the third hypothesis. But the second test I performed renders that argument irrelevant (explanation further down).
The first test establishes the following:
1. That different papers fail at different rates, depending on their general structure - coating on polythene on paper, or coating on baryta on paper, or coating directly on paper.
2. That the mechanism of failure seems to differ between papers - delamination of the coating on RC papers, delamination and cracking of the baryta layer in the baryta papers, and no obvious failure seen in the coating-on-paper papers (although other studies have shown that microporous layers develop microscopic cracks under heavy ink loads).
You contended that the test is irrelevant, because putting prints up against a window exposes them to much greater peak temperatures as compared to a framed, matted print hanging on a wall away from the window and exposed to sunlight for 1-2 hours at a time. The second test refutes that.
The second test establishes the following:
1. That the temperature of an unframed piece of white paper remains near the ambient room temperature (1 or 2 degrees warmer) even when in direct sunlight.
2. That the front and back of a piece of paper remain within around half a degree of each other when one side is exposed to strong solar irradiation.
3. That the air temperature in the small gap between the paper and the window is similar (less than 2 degrees warmer) to the air temperature at the back of the room, out of direct sunlight.
You contend that these small temperature differences matter, however small they may be and, therefore, invalidates the results. However, the other part of the test completely invalidates your argument. The tests involving black paper and framed paper establish:
4. That dark paper (e.g. prints) becomes a lot hotter than white paper when exposed to the same level of solar irradiation, greatly exceeding the surrounding air temperature. Therefore, a typical print would become much hotter than my unprinted paper samples when exposed to the same level of sunlight.
5. That prints enclosed in a frame behind glass get a lot hotter than unframed prints or paper, even when the prints/frames are well back from the window. Therefore, a framed print gets a lot hotter than an unframed print when exposed to sunlight. That's not to say that there aren't other protective features of framing that make it worthwhile, but that protection from the thermal effects of direct sunlight isn't one of them.
The fourth and fifth findings of the second test render all the arguments about 'extreme temperatures' completely invalid, since they show that a piece of printed paper well back from the window (but still receiving an hour or so of direct sunlight) and enclosed within a frame gets much hotter than a white piece of paper up against the window - much more than the 1 or 2 degrees above room air temperature experienced by the unframed white paper.
Essentially, what the second set of tests show is that the 'extreme temperature' argument against the results of the first test are invalid, since they show that a framed print will be exposed to much higher temperatures than a white, unframed piece of paper ever will.
-
Not surprising, given that they're dye inks on porous paper.
I wonder if results would have been better using swellable paper rather than microporous.
It'd be really nice to find a type of coated paper that remains supple, flexes with the paper and won't peel, crack or disintegrate over time. 'Infused' inkjet coatings certainly fit the bill (there being no layer to separate from the paper) - but I can't find anyone who makes one at the moment (although they sell infused, uncoated canvas). Stable coatings are certainly possible - after all, we have egg tempera paintings on wood dating from the early days of the Roman Empire. If one of these types of coated paper turns out to be stable, I wouldn't have to go through all this experimentation and accept a compromised gamut to produce highly-conservable premium-edition prints!
Do you have any photos of your Biotop/Z3200 prints that you can post, so I can see what sort of gamut you're getting?
The Iris dyes on uncoated Arches were more light resistant than on the inkjet coated Hahnemühle. It is not the paper porosity but the coating porosity etc that had an effect. At that time the pH grade of the inks and the pH of the media was considered to play a role on that aspect. Dyes + cotton could build on textile coloring technology and did so to a degree. Swellable paper was the other direction that delivered better lightfastness for dyes.
The Bockingford for inkjet is no longer in production? That was one of the first infused papers John Edmund and the infusion expert at the background had a hand in. I actually could not see much difference in the results between the plain Bockingford and the infused.
The Biotop 3 that I use is for design students that need a semi offset quality prop. I do not use it for longevity projects etc. There are more non-inkjet papers I use for similar tasks. Have to make some scans but this is not the Nirvana of inkjet printing you will see. It is not the Mondi BIO TOP 3® high-speed inkjet type that is more aimed at inkjet printing. Felix Schoeller has a range and you will find Scandinavian paper research PDFs aiming for that quality too.
For that matter, years ago I did coat Arches Velin with a (silkscreen) coating made by Marabu for CDs to be printed. UV curing coating, I think Marabu sold that coating to a Japanese firm later on. The image quality became better than the uncoated Arches gave but the image still had little wetting resistance.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
-
The Iris dyes on uncoated Arches were more light resistant than on the inkjet coated Hahnemühle. It is not the paper porosity but the coating porosity etc that had an effect. At that time the pH grade of the inks and the pH of the media was considered to play a role on that aspect. Dyes + cotton could build on textile coloring technology and did so to a degree. Swellable paper was the other direction that delivered better lightfastness for dyes.
The Bockingford for inkjet is no longer in production? That was one of the first infused papers John Edmund and the infusion expert at the background had a hand in. I actually could not see much difference in the results between the plain Bockingford and the infused.
The Biotop 3 that I use is for design students that need a semi offset quality prop. I do not use it for longevity projects etc. There are more non-inkjet papers I use for similar tasks. Have to make some scans but this is not the Nirvana of inkjet printing you will see. It is not the Mondi BIO TOP 3® high-speed inkjet type that is more aimed at inkjet printing. Felix Schoeller has a range and you will find Scandinavian paper research PDFs aiming for that quality too.
For that matter, years ago I did coat Arches Velin with a (silkscreen) coating made by Marabu for CDs to be printed. UV curing coating, I think Marabu sold that coating to a Japanese firm later on. The image quality became better than the uncoated Arches gave but the image still had little wetting resistance.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
That's what I meant - microporous coatings on paper. All paper is porous anyway.
Bockingford is only available up to 13x19" size, and not at all in roll form. Not that it's particularly impressive, anyway.
Would you consider the colour images you're getting with the Z3200 and BioTop paper to be photo quality? What have you used successfully for longevity work?
-
Would you consider the colour images you're getting with the Z3200 and BioTop paper to be photo quality? What have you used successfully for longevity work?
No, not photo quality, something between magazine and newspaper quality. For B&W there is less lost. It is possible to get close to the old rotogravure B&W book printing that I always liked. An old fashioned taste though.
What Aardenburg-Imaging showed as lasting; HM + Canson paper qualities + Z3100 and Z3200 Vivera pigments and more and more used with protective sprays. That does not cover the mechanical issues like abrasion and coating bond. Something I was well aware off but have no answer on right now other than framing behind glass.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
-
No, not photo quality, something between magazine and newspaper quality. For B&W there is less lost. It is possible to get close to the old rotogravure B&W book printing that I always liked. An old fashioned taste though.
That's disappointing. I would certainly classify Piezography or MIS black-and-white inks on Arches or Fabriano paper as being photo quality - they're equal to any platinum print I've seen, with a Dmax similar to coated matte paper. But, obviously, colour is more difficult, being that you need to widen the gamut as well as increase the density, and you have the total ink limit to contend with as well.
-
That's disappointing. I would certainly classify Piezography or MIS black-and-white inks on Arches or Fabriano paper as being photo quality - they're equal to any platinum print I've seen, with a Dmax similar to coated matte paper. But, obviously, colour is more difficult, being that you need to widen the gamut as well as increase the density, and you have the total ink limit to contend with as well.
There is a range of ordinary inkjet papers with thin coatings from companies like Felix Schoeller, Mitsubishi, etc that certainly create color photo quality prints. The gloss with dye inks, the matte for both types of ink. The papers you baked in the sun had thicker, more complex coatings than used in the ordinary qualities and the last may stand the treatment better, at least on the coating bond.
Blacks on uncoated papers like Arches with the inks you mention is visibly lower than on coated papers. The Dmax measurements show that too. On Biotop 3 the best measurement shows a 1.5 D, L 20.70, Paul hits at approx L 18.0 ( 1.6 D?) with Eboni on uncoated Arches, Photorag with HP Vivera can get to 1.82 D. It is not just that but bleeding of detail, mottle in gradations etc that count for me. I do not use QTR but an ordinary driver and can not boost the blacks though I doubt that would gain much either given the bleeding. For Platinum/Palladium prints I see Dmax values reported from 1.3 to 1.8.
The surface of the prints made on uncoated paper can be handled far rougher than coated inkjet papers allow. Offset on opposite pages in books is no issue either. A big plus. So yes, what Mark tried to achieve with Hawk Mountain etc could solve other issues too. There is a thing we should not forget though, with pigment inks the gain in Dmax and gamut is by keeping the pigment layer at the top which inevitably leads to a delicate surface.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.
-
There is a range of ordinary inkjet papers with thin coatings from companies like Felix Schoeller, Mitsubishi, etc that certainly create color photo quality prints. The gloss with dye inks, the matte for both types of ink. The papers you baked in the sun had thicker, more complex coatings than used in the ordinary qualities and the last may stand the treatment better, at least on the coating bond.
Thanks. I had a look at those websites. Unfortunately, it seems that these are commercial-grade papers designed for large-volume printing, not fine art papers. They're certainly not cotton rag, and I doubt they are OBA-free either - if they were, the manufacturers would probably advertise them as such. They may not even be alpha-cellulose or acid-free. Without further information, certainly not something I'd be printing archival works on.
Blacks on uncoated papers like Arches with the inks you mention is visibly lower than on coated papers. The Dmax measurements show that too. On Biotop 3 the best measurement shows a 1.5 D, L 20.70, Paul hits at approx L 18.0 ( 1.6 D?) with Eboni on uncoated Arches, Photorag with HP Vivera can get to 1.82 D. It is not just that but bleeding of detail, mottle in gradations etc that count for me. I do not use QTR but an ordinary driver and can not boost the blacks though I doubt that would gain much either given the bleeding. For Platinum/Palladium prints I see Dmax values reported from 1.3 to 1.8.
I've seen 1.7 using Cone inks and a printer with a makeshift platen heater set at 55 degrees. No doubt many matte papers can exceed this. But a lot of other matte papers - particularly the heavily-textured ones - only reach around 1.6.
Where did you see a platinum print with a Dmax of 1.8? It's generally around 1.4, although it can be pushed up a bit more (to around 1.5-1.55) using multiple passes. At least that's out of the ones I've seen.
The surface of the prints made on uncoated paper can be handled far rougher than coated inkjet papers allow. Offset on opposite pages in books is no issue either. A big plus. So yes, what Mark tried to achieve with Hawk Mountain etc could solve other issues too. There is a thing we should not forget though, with pigment inks the gain in Dmax and gamut is by keeping the pigment layer at the top which inevitably leads to a delicate surface.
That's with dye inks. Pigments, in the cross-sectional micrographs I've seen, all stay on, or very close to the surface. I thought the loss of Dmax and gamut was due to the need to restrict ink load due to dot gain and drying times - accelerating the drying process allows for a greater ink load.
No doubt the surface would be more delicate than with a dye print. But delicate is OK - as long as the surface (and the image) doesn't start disintegrating even without abrasion, just through expansion and contraction of the substrate and minimal flexion.
What Aardenburg-Imaging showed as lasting; HM + Canson paper qualities + Z3100 and Z3200 Vivera pigments and more and more used with protective sprays. That does not cover the mechanical issues like abrasion and coating bond. Something I was well aware off but have no answer on right now other than framing behind glass.
The coating-on-paper papers, with no extra layer in between the coating and the paper, seemed to hold up very well -at least when uninked. Unfortunately, inkjet coatings are well known for developing micro-cracks when heavily inked... Still, something like BC Pura Velvet or Pura Smooth seems like it would be a good compromise - great lightfastness, good gamut and physically durable as far as coated papers are concerned.
The Kernewek line of canvas (by Kernow, tested on Aardenburg) look interesting. It's uncoated, unprimed cotton or poly-cotton canvas that's basically been soaked in inkjet receptive coating (so no coating to crack or flake off), has a better gamut and Dmax than most canvas and has very good print permanence too. Unfortunately, it's not paper...
You mentioned that your print results on uncoated paper were somewhere between newspaper and magazine output. I assume you mean in terms of gamut and dot-gain, not in terms of the dot pattern (which tends to be horribly low-resolution in both newsprint and cheap magazines)? Would you say the output is somewhat similar to that of a watercolour painting?
-
OK, Shadow.
Yours is a comprehensive test from which direct results can be extrapolated for real life situations and there is no possibility that any of the multitude of factors could be an influence on the results - just the ones you've decided are valid.
I expect you'll now be able to provide us with suggested media life times when mounted behind glass on a wall, right?
You obviously know a lot about this subject and have a scientific background of some sort (or at least a strong interest), so I can not understand how you fail to see that whilst very interesting and possibly a tell-tale of something, these are not results from which useful predictions can be made, nor can you safely draw the conclusions which you are given you have no isolated a numer of the potential contributing factors.
So, I don't know. It's a good subject, you're obviously well informed and I think there's a lot of value here but I don't get you - you're almost rabid in insisting your results are beyond question and despite some interesting discussion you still draw unsupported conclusions. I have *zero* reason to want to deny your results - no vested interest or counter agenda. Maybe you're far too clever for me and I don't get it - I accept that as a distinct possibility on any subject, including those within my expertise.
I said before I thought I sounded overly harsh at times and it wasn't my intent, so I'll bow out now - I don't think I can discuss things with you effectively.
/shrug
-
OK, Shadow.
Yours is a comprehensive test from which direct results can be extrapolated for real life situations and there is no possibility that any of the multitude of factors could be an influence on the results - just the ones you've decided are valid.
I expect you'll now be able to provide us with suggested media life times when mounted behind glass on a wall, right?
You obviously know a lot about this subject and have a scientific background of some sort (or at least a strong interest), so I can not understand how you fail to see that whilst very interesting and possibly a tell-tale of something, these are not results from which useful predictions can be made, nor can you safely draw the conclusions which you are given you have no isolated a numer of the potential contributing factors.
So, I don't know. It's a good subject, you're obviously well informed and I think there's a lot of value here but I don't get you - you're almost rabid in insisting your results are beyond question and despite some interesting discussion you still draw unsupported conclusions. I have *zero* reason to want to deny your results - no vested interest or counter agenda. Maybe you're far too clever for me and I don't get it - I accept that as a distinct possibility on any subject, including those within my expertise.
I said before I thought I sounded overly harsh at times and it wasn't my intent, so I'll bow out now - I don't think I can discuss things with you effectively.
/shrug
Nope.
It's a qualitative test, not a quantitative test, without the intent to predict absolute lifespans but with the ability to predict relative lifespans (which papers will fail before others) and mechanisms of failure.
The issue you kept harping about was thermal effects. I also showed that any framed print exposed to direct sunlight will get a lot hotter than an unframed piece of white paper, which completely dismisses that theory, in that any thermal effects contributing to deterioration of plain, white paper will also be there, and in much greater intensity, in framed, printed paper. If you disregard test results you don't like and which don't fit your preconceptions of reality (namely, your hypothesis that framed prints exposed to sunlight don't get as hot as unframed white paper exposed to sunlight) then you're the one pushing an agenda. So far, you haven't presented a single counter-argument backed by either experimental data or logically-presented scientific theory - when presented with evidence contradicting your 'thermal effects' argument, you've essentially done the debating equivalent of running into a corner and sulking.
Frankly, I'm not interested in how long a print will last in a museum or in the hands of conservators. I'm interested in how to produce a print that can last for centuries in untrained hands and uncontrolled environments. Which means wildly-swinging humidity and occasional exposure to direct sunlight.
Besides, it's both pointless and near-impossible to test any of these factors in isolation. If you test for UV exposure using xenon lamps, you'll heat up the print. If you heat up the print to test for thermal effects, you'll also dramatically lower the relative humidity. And deterioration requires more than any one of these factors. Expose a print to intense UV light in space and it will only slowly fade, since UV light degrades ink by catalysing reactions with atmospheric molecules. Expose a print to swinging humidity, but no UV light or atmospheric pollutants, and it will only slowly degrade, since embrittlement of PVOH-based microporous coatings is based on UV and pollutant exposure.
-
Where did you see a platinum print with a Dmax of 1.8? It's generally around 1.4, although it can be pushed up a bit more (to around 1.5-1.55) using multiple passes. At least that's out of the ones I've seen.
That's with dye inks. Pigments, in the cross-sectional micrographs I've seen, all stay on, or very close to the surface. I thought the loss of Dmax and gamut was due to the need to restrict ink load due to dot gain and drying times - accelerating the drying process allows for a greater ink load.
You mentioned that your print results on uncoated paper were somewhere between newspaper and magazine output. I assume you mean in terms of gamut and dot-gain, not in terms of the dot pattern (which tends to be horribly low-resolution in both newsprint and cheap magazines)? Would you say the output is somewhat similar to that of a watercolour painting?
http://www8.clikpic.com/platinumprinting/section444277.html and on more sites. I wrote "reports seen", there is no platinum print here and I do not like to compare on memory.
Prints made with pigment inkjet inks on uncoated papers have the pigment particles embedded between the paper fibers, in the sizing, whatever. That makes the prints less delicate, based on sheets lying around here. You will not get a much higher Dmax even if you sacrifice detail and lay down ink with a paper setting for Photorag etc. You might gain Dmax with multiple print runs. Get a flatbed printer then with a hot plate. When you achieve that the pigment will be bare on the surface and be as delicate as it is on coated paper.
No of course not the raster screening of a newspaper image but gamut etc. Between newsprint and magazine print, not cheap magazine. There must be an offset print shop where you can get some sheets Biotop 3 or similar and feed it through the Z3200 you have an eye on. Anyway it is not the paper you intend to use. It was just to illustrate what the quality of a Z3200 + uncoated paper delivers, you wondered about that.
I too have to finish this message exchange, got work to do and keep some time for other threads.
-
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.