Ink / Paper absorbtion rates - what's happening?

[MHMG]

May I point out that the evidence had from prior electron microscopic  sampling of side views of cut paper has been rendered obsolete, since it has been recognized that side view sections cut with the best of blades alter the samples through squashing of the materials, no matter how careful.  New techniques render historical and traditional views inadequate.  A company called Sappi, cuts paper with an argon beam instead of a blade to aide in more accurate investigations.


Mark

While I agree that microtomy and tradtional cross-sectional analysis has been superceded in some instances by newer tehniques, it is still practical and far from inadequate for many coated paper and media investigations.  Certainly competent enough of a method to answer the questions being discussed in this thread 

cheers,
Mark
http://www.aardenburg-imaging.com

[shadowblade]

Shadowblade, you know I respect your opinions and your background, etc.  May I point out that the evidence had from prior electron microscopic  sampling of side views of cut paper has been rendered obsolete, since it has been recognized that side view sections cut with the best of blades alter the samples through squashing of the materials, no matter how careful.  New techniques render historical and traditional views inadequate.  A company called Sappi, cuts paper with an argon beam instead of a blade to aide in more accurate investigations.

I'm going on microscope views of cut paper, since I don't have access to a laser cutter.

Are there any images available of pigment penetrating into the base layer in a correctly-made (i.e. not overinked) print, cut using a laser cutter?

As I say, without the equipment, expertise and background to back it up, I have a hunch that the ink does combine and lock into the fibers, and I will stick to my opinion, while at the same time thinking about what you are saying.  I am not talking about an exaggerated sloppy combinations, just a level of "key" which enables a combinatorial intermingling of paper fibers with all the elements making up the interaction of ink and coating.  I don't think the paper fiber can be left out of the equation, or why bother having matte papers at all?  The interaction of the ink with the paper and the coating is significant in a combinatorial sense.

What specific interactions do you think would happen, or could happen?

Clearly, interaction between pigment and substrate is not required, otherwise gloss papers, baryta papers, RC papers and films wouldn't work at all. In fact, a substrate isn't technically even required - you could print on a solid sheet of inkjet coating if you wanted to. Really, it's better to view an aqueous inkjet print as a microporous layer, holding an image, attached to a supporting and light-reflecting substrate. The microporous layer essentially acts like a filter for ink, separating out the solid pigment particles and allowing the liquid to pass through. No filter is perfect, though; when the filter is saturated, solid particles can also start to get through.

Certainly, there will be interaction between the carrier fluid and the substrate, provided it can reach the substrate. But, even if the pigment reaches the substrate, I can't see how there would be any chemical interactions between the pigment and the substrate at all. Remember, the resin encapsulating the pigment particles is designed to be as unreactive and chemically and physically stable as possible.

Why would you think there would be interaction between the pigment and the paper? Even if the pigment reaches the substrate, it's just going to sit on the surface of the fibres or sink deeper in to the paper base, moving through the gaps between the fibres. Pigment particles are a bit like dust or sand - they are solid particles, encapsulated in an unreactive resin. They just sit on whatever surface they adhere to, not reacting with them. Paper fibres are also stable, solid structures. Stable solid materials don't tend to do much when brought into contact with each other, except sometimes at extreme pressures and temperatures (at which point they're usually no longer solid nor stable).

Matte paper - like any other paper - is used for its appearance. Specifically, its texture. There are a lot of different papers out there, and a lot of different pigment ink formulations, and every single one of them is a usable combination. If pigment-on-substrate interaction occurred to any significant degree and affected the final image, there should be a lot of printer-paper combinations that just don't work.

[Mark Lindquist]

While I agree that microtomy and tradtional cross-sectional analysis has been superceded in some instances by newer tehniques, it is still practical and far from inadequate for many coated paper and media investigations.  Certainly competent enough of a method to answer the questions being discussed in this thread 

cheers,
Mark
http://www.aardenburg-imaging.com

OK Mark, fair enough.  I'll accept that coming from you.   

[MHMG]

The attached photo is a digital scan from a 35mm slide made with film camera attached to conventional microscope. This simple cross-sectional analysis is of a traditional RC chromogenic color print paper. From top to bottom one can make out:

1)very thin "supercoat" layer of gelatin (a bit hard to see but still observable in this photo, the clear supercoat gelatin layer is used to improve abrasion resistance of the dye-based image).
2) isolated cyan dye layer
3) isolated magenta dye layer
4)isolated yellow dye layer (all dye layers formed via color coupler chemistry during the silver halide processing step)
5) the dark and opaque layer imaged by the brightfield method is the TiO2 pigment white particles embedded in the top Polyethylene (PE) coating layer (the PE layers keep the water out of the paper core during processing).
5) The paper base sheet itself showing fibers and filler materials like calcium carbonate)
6) the clear PE bottom layer (i.e no TiO2 in this bottom PE layer) which lastly 7) has a thin gelatin layer (the dark band at the bottom) to give anti-curl layer assistance to the whole multl coated print structure. This bottom PE layer  also has a rough calendared bottom surface which is why is looks so wavy. The calendaring gives this RC print a matte textured feel on the back side of the print, but it's all done with the roughened PE in this particular RC paper. Other RC papers actually embed some rough silica particles to perform the matting trick on the verso of the print.

Anyway, I made this photo over 20 years ago. With today's digital cameras, the image quality would be better yet, but even with the limitations of the cross-sectioning technique and film photography at the time, the observer can distinguish every layer sandwiched into this RC print paper technology.  Inkjet papers have coatings  of similar thicknesses, so this traditional microscopy technique should readily show whether colorants have reached the paper core or not.  My experience is that dye based inkjet prints kept under humid conditions will allow the dyes to eventually diffuse beyond the primary ink receptor layer because unlike tradititional wet processed color prints, there is insufficient mordanting chemistry to keep those water soluble dye molecules anchored where they first dry down. In contrast, pigment prints will have those pigment particles trapped/adhered nicely very close to the top surface of the ink receptor layer, and they aren't going to go anywhere even though the water and glycol components will indeed diffuse further into the media. The glycol diffusion is going to go on for a very long time, and glycols are humectants, so in particular for RC inkjet papers, I suspect outgassing issues are not entirely resolved merely by letting inkjet prints "dry down" for a week or two before framing. The slow but inevitable off gassing will eventually require glazings to be removed, cleaned and reinstalled as time goes by.

I hope this photo helps frame (no pun intended) some of the points discussed in this thread

Edit: I should also mention that this photo shows a Dmax region of the RC color print, so all of the dye forming layers have generated maximum dye content during processing.

cheers,
Mark
http://www.aardenburg-imaging.com

[Mark Lindquist]

This is very interesting Mark.  For 20 years ago, not bad.  (To say the least).

Your findings are enlightening.  You mentioned that inkjet coatings have coatings of similar thicknesses, etc., but I'm wondering if these coatings are, in today's time frame, speaking specifically about fine art Matte papers, similar.

I am particularly interested in your explanation of how and why dry down occurs and the implications regarding off-gassing.

Would this allow us to conclude that the phenomenon of the print "coming into focus" (a poor analogy) or actually becoming a cleaner, clearer print in a 24 to 48 hour period be due to evaporation?

In speaking just about Fine Art Matte papers, say Breathing Color Pura Smooth, and Epson Ultra Smooth Fine Art and any other equivalents, does the "wetness" meaning combinations of glycols, inks, etc., dry sufficiently via evaporation so that the print becomes altered at it's surface?

Can you shed light on this phenomenon?

I would be interested in a modern or updated microscopy test on fine art matte papers, during various phases and times of drying.  Will pigment based inks diffuse similarly as your example from 20 years ago on an RC paper be the same as a current fine art matte paper?

I appreciate your taking the time to contribute this information, and would be interested in a similar test on Fine Art Matte papers.

Mark

[Mark Lindquist]

So for fun, I decided to see how a non-coated paper, properly profiled and calibrated using "Fine Art Papers More Ink" preset would fare without an inkjet coating and none of the barriers and glycols and humectants, etc, found in typical inkjet substrates.

I used Bienfang Drawing paper No. 527K Bristol Velum Surface for Pencil

There are two images below attached.  The copies were made under really crappy florescent lighting.

I thought that there would be tremendous ink smearing, blotchy impossible to read colors, utterly devastating impossible ink blotting.

Hmmmmm.  No such luck.

The first shows the calibration chart and the Atkins test image.

The second shows a 100% crop.

Granted, these images are nothing like what the Atkinson chart should actually look like on a coated paper.

But.....

Gotta say those blacks look pretty danged black - the black and white doesn't look bad.  For no smearing.

Why and how could/would ink go down into the surface of matte papers, and what could it possibly do but mess up the print?

Mark

[shadowblade]

So for fun, I decided to see how a non-coated paper, properly profiled and calibrated using "Fine Art Papers More Ink" preset would fare without an inkjet coating and none of the barriers and glycols and humectants, etc, found in typical inkjet substrates.

I used Bienfang Drawing paper No. 527K Bristol Velum Surface for Pencil

There are two images below attached.  The copies were made under really crappy florescent lighting.

I thought that there would be tremendous ink smearing, blotchy impossible to read colors, utterly devastating impossible ink blotting.

Hmmmmm.  No such luck.

The first shows the calibration chart and the Atkins test image.

The second shows a 100% crop.

Granted, these images are nothing like what the Atkinson chart should actually look like on a coated paper.

But.....

Gotta say those blacks look pretty danged black - the black and white doesn't look bad.  For no smearing.

Why and how could/would ink go down into the surface of matte papers, and what could it possibly do but mess up the print?

Mark

After profiling the paper, what ink limits did you end up with? I'm guessing they were significantly lower than the ink limits on coated paper.

The difficulties with printing on uncoated paper are dot gain and non-uniformity of the surface. With regards to dot gain, this is because the carrier fluid - still containing the pigment - spreads along the randomly-distributed paper fibres, thus spreading more-or-less evenly in three dimensions - it spreads outwards as much as it spreads into the paper, causing dot gain. In contrast, on a coated paper, the ink is drawn down through the coating much more than it travels along the coating, and the vast majority of pigment is filtered by the topmost microporous layer. Think of an ink dot on uncoated paper as being more akin to a hemisphere spreading out from the intial do, and an ink dot on coated paper being more like a cylinder extending behind the initial dot, with most of the pigment being filtered out at the topmost layer of the cylinder. With regards to surface homogeneity, an inkjet coating is a more-or-less homogenous layer, which stays the same regardless of the paper texture underneath it. its surface irregularity is at a much finer scale than the surface irregularity of paper. With uncoated paper, the surface features exist at a much larger scale - whether an ink dot lands directly on a paper fibre, in a space in between fibres or on something else determines what the dot looks like and how it spreads. This is what causes the 'splotchiness' which can sometimes happen.

You can counteract the dot gain by reducing the ink load - less ink means that the pigment doesn't spread as far. Restrict it enough and the dots end up the same size as on coated paper, meaning minimal loss of sharpness (although the dots will still have feathery edges rather than the distinct, circular/square dots seen on coated paper). But this lower ink load also means less pigment, which means less colour. This could be compensated for by using a double-printing/re-registration process - the thing about uncoated paper is that, even though it can only handle a small amount of ink at the one time, you can't really over-ink it, since there's no surface coating which can be saturated. You can overprint it again and again. Naturally, this would only really be feasible with a flatbed aqueous printer, or some very good RIP software.

I've had a number of prints made using carbon inks on uncoated paper - they turned out very well, have Dmax to match many matte coated papers (although not the best ones) and far exceeding that of platinum prints, and should last even longer than platinum prints. Doubtlessly, a double-printing approach could improve the Dmax even more.

[Mark Lindquist]

After profiling the paper, what ink limits did you end up with? I'm guessing they were significantly lower than the ink limits on coated paper.

I kept the ink limit exactly the same as when using a coated paper specifically to prove the point that ink can bond to matte surfaces and create a stronger color base.  The Quad Ink setting has an ink limit setting of 60.  Many PK settings for coated papers are 30.

I just went to check the print, and indeed, as it is drying, the image is becoming clearer, cleaner, and sharper.  In theory, what you say sounds good, yet in practice, the reality varries.  The matte paper can carry the ink in an acceptable manner providing calibration and profiling are done carefully and with a correct setting.  Either that ot the Z3200 is nothing short of miraculous. 

The exact setting that would have been used on a coated fine art ink jet paper.  Everything within certain parameters of acceptability meaning "in the ballpark".

If ink migrates through the microporous structure of coatings, I doubt very much it would harm the print in the specific case of Fine Art Matte Papers.  I do believe it could strengthen the finished print providing a   stronger base than merely residing solely on a layer suspended above the paper.

RC papers and coated shiny papers are not within the scope of my premise.  I believe this applies only to Fine Art Matte Papers. 

At any rate, I'll not argue further, as scientifically, I csan not prove this, and anecdotal examples admittedly fall short of definitive proof.  So I have my theory which is somewhat demonstrated by the print on uncoated paper. 

Either way, it is not really what the original topic was about, which was about dry-down time and the print improving over that waiting period.

It has been an interesting distraction, however.

Mark

Edits for spelling/typos

[shadowblade]

I kept the ink limit exactly the same as when using a coated paper specifically to prove the point that ink can bond to matte surfaces and create a stronger color base.  The Quad Ink setting has an ink limit setting of 60.  Many PK settings for coated papers are 30.

I just went to check the print, and indeed, as it is drying, the image is becoming clearer, cleaner, and sharper.  In theory, what you say sounds good, yet in practice, the reality varries.  The matte paper can carry the ink in an acceptable manner providing calibration and profiling are done carefully and with a correct setting. 

Exactly - it's all about the profiling. Profiling takes into account dot gain and everything else. The fact that the maximum allowable ink limit is 60 doesn't meant that that's how much is actually put down (although it wouldn't be unreasonable for blacks) - I would think that, due to the effects of dot gain, the actual amount of ink put down to produce any given colour (that lies within gamut) would be less than for a coated paper. But you'd have to look at the linearisation curves being generated to see this, not just the ink limit.

The image becoming clearer and sharper makes perfect sense - as it dries, light goes from reflecting off a grey, saturated paper base to reflecting off a white base. Nothing to do with whether

Either that ot the Z3200 is nothing short of miraculous.

The exact setting that would have been used on a coated fine art ink jet paper.  Everything within certain parameters of acceptability meaning "in the ballpark".

It's not the same setting, though. You creased a profile for the paper. That's one of the major strengths of the Z3200 - it's very straightforward to create a new profile and print on just about anything.

If ink migrates through the microporous structure of coatings, I doubt very much it would harm the print in the specific case of Fine Art Matte Papers.  I do believe it could strengthen the finished print providing a   stronger base than merely residing solely on a layer suspended above the paper.

What do you mean by 'harm the print'? Also, what do you mean by 'ink'? Do you mean the pigment, specifically? Pigment particles are a bit like dust - it doesn't really form a solid bond with anything. It just gets stuck  in the microporous coating, or on the external sizing of the paper fibres, but there's not much actually holding it to those surfaces other than friction and adsorption - it's certainly not any sort of adhesion. Particles that did adhere would be difficult to make ink from, because all the particles would stick together and rapidly give you a congealed mass at the bottom of the ink tank, unable to pass through the tubing, let alone through the print head. So, for that (and many other) reasons, they use nonreactive, non-adherent resin encapsulation - which, just like dust, can be easily brushed off a smooth printed surface. Just see what happens when you print on uncoated plastic or metal - there's no adhesion at all. Matte printed surfaces are more protected than completely smooth surfaces, because the particles are stuck in the microporous layer and can't be brushed off so easily, and gloss is even more protected, since the particles are stuck behind the gloss membrane in front of the print. But what's holding them there isn't any sort of adhesive force, but mere friction and mechanical obstruction, like fish caught in a net.

You can demonstrate this easily. Pour some ink into a container, and allow it to air-dry completely. You're left with a fine, dust-like powder. That's the encapsulated pigment - all the water, glycols, etc. have all evaporated. Rub it on a piece of uncoated paper. You'll find it has no adhesive properties whatsoever.

At any rate, I'll not argue further, as scientifically, I csan not prove this, and anecdotal examples admittedly fall short of definitive proof.  So I have my theory which is somewhat demonstrated by the print on uncoated paper. 

Either way, it is not really what the original topic was about, which was about dry-down time and the print improving over that waiting period.

It has been an interesting distraction, however.

Mark

I'm still not quite sure what the uncoated paper experiment was meant to demonstrate. That it's possible to print on uncoated paper?

[Mark Lindquist]

As I said, Doc:

"...At any rate, I'll not argue further, as scientifically, I can not prove this, and anecdotal examples admittedly fall short of definitive proof.  So I have my theory which is somewhat demonstrated by the print on uncoated paper..."

Give it a rest my friend.

[Paul Roark]

I hesitate to get into the middle of one of these discussions, but FWIW, here are a few of my observations and what I've heard regarding a couple of the issues.

Printing on watercolor paper -- Arches Hot Press in particular -- can result in very good images, at least for black and white.  My QTR profiles go easy on the ink limits for the dilute inks, but heavy at the black end.  The Arches dmax is not reached until about 125% of the maximum QTR ink load.  So, I have 2 MK ink positions in my printers. 

The Arches smoothness will not be as good as a coated paper, but at "full sheet" (22x30 inches in the US) size, the normal viewer will not see the difference, and the critical viewer's appreciation of the underlying medium may offset the unevenness of some of the plain dark gray areas (like my heavily filtered skies). 

If the loose fibers on the top surface of Arches are likely to cause too many "shadows" (white spots) in these dark, plain areas, I suggest printing on the backside of the paper.  It has a texture I actually prefer in some respects. It seems to have fewer fibers sticking up off the surface.

BTW, remember to iron the deckle edges to avoid head strikes, and have fun figuring out how to deal with that deckle edge throwing off the printer's electric eye and image centering algorithms.

The advantages of a matte paper (any cotton based paper, probably) include that glycols have an "affinity" for cellulose and will likely just wrap themselves around those fibers and stay there, not outgas.  (This is according to a PhD chemist.)  The cellulose base, and particularly a cotton base, ends up taking care of much of the ink base products.  The barrier papers have a problem in this respect.

I have and am backing away from the very dilute gray inks used in many dedicated B&W inksets because, in part, I don't think we know what all those base chemicals are going to do in the long run.  Even in the short run, I see problems with putting too much water on the print.  Our medium has proved itself worthy at this point.  I no longer worry about people putting a loupe up to one of my prints and discovering that it is composed to tiny dots.  I rather agree with the OEM companies that the LLK density is about as light as we usually need.  After that, I wonder if the excess base chemicals are going to do more harm than good.

Paul
www.PaulRoark.com
http://www.paulroark.com/BW-Info/

[Mark D Segal]

..........

Either way, it is not really what the original topic was about, which was about dry-down time and the print improving over that waiting period.

It has been an interesting distraction, however.

Mark

Edits for spelling/typos

Yes, I agree - it is an interesting discussion and reminds one that ink, paper and profiles are very critical variables in determining gamut and print quality, however defined. On the specific issue you raised about dry down time and print improvement over that period, not being an ink and paper chemist I cannot make any definitive statements about what really happens "under the hood", so this observation is empirical - i.e. based on what I see, and it is specific largely to several different PK papers printed in Epson 4900 or P800 printers using OEM inks and printer drivers mainly with custom icc profiles made in XRite software, so nothing exotic here. I find that I see some improvement in print clarity and shadow detail the morning after the night before, during which the prints are out-gassing in open air. The next morning I put them in archival storage boxes, the prints simply stacked. I went back to one of these boxes of prints I created some years ago, examined especially the backs of the prints, and saw no evidence of anything suggesting that chemical reactions having noticeable impacts were still occurring. So perhaps the real question is how much dry-down time is practically important; this experience for these materials would suggest about 12~24 hours.

[Ernst Dinkla]

Exactly - it's all about the profiling. Profiling takes into account dot gain and everything else. The fact that the maximum allowable ink limit is 60 doesn't meant that that's how much is actually put down (although it wouldn't be unreasonable for blacks) - I would think that, due to the effects of dot gain, the actual amount of ink put down to produce any given colour (that lies within gamut) would be less than for a coated paper. But you'd have to look at the linearisation curves being generated to see this, not just the ink limit.

The image becoming clearer and sharper makes perfect sense - as it dries, light goes from reflecting off a grey, saturated paper base to reflecting off a white base. Nothing to do with whether

It's not the same setting, though. You creased a profile for the paper. That's one of the major strengths of the Z3200 - it's very straightforward to create a new profile and print on just about anything.

What do you mean by 'harm the print'? Also, what do you mean by 'ink'? Do you mean the pigment, specifically? Pigment particles are a bit like dust - it doesn't really form a solid bond with anything. It just gets stuck  in the microporous coating, or on the external sizing of the paper fibres, but there's not much actually holding it to those surfaces other than friction and adsorption - it's certainly not any sort of adhesion. Particles that did adhere would be difficult to make ink from, because all the particles would stick together and rapidly give you a congealed mass at the bottom of the ink tank, unable to pass through the tubing, let alone through the print head. So, for that (and many other) reasons, they use nonreactive, non-adherent resin encapsulation - which, just like dust, can be easily brushed off a smooth printed surface. Just see what happens when you print on uncoated plastic or metal - there's no adhesion at all. Matte printed surfaces are more protected than completely smooth surfaces, because the particles are stuck in the microporous layer and can't be brushed off so easily, and gloss is even more protected, since the particles are stuck behind the gloss membrane in front of the print. But what's holding them there isn't any sort of adhesive force, but mere friction and mechanical obstruction, like fish caught in a net.

You can demonstrate this easily. Pour some ink into a container, and allow it to air-dry completely. You're left with a fine, dust-like powder. That's the encapsulated pigment - all the water, glycols, etc. have all evaporated. Rub it on a piece of uncoated paper. You'll find it has no adhesive properties whatsoever.

I'm still not quite sure what the uncoated paper experiment was meant to demonstrate. That it's possible to print on uncoated paper?

In custom RGB-device printer profiling, like most OEM drivers require, there is no access to the ink limitations, black generation etc. And the HP calibration only linearises what it sees as non linear in the calibration target, Dmax and maximum chroma will not be changed and by that the inklimits neither. The ink settings are in the media preset used, they do not change on profiling and only change within the ink limit range on calibration. The measurements + RGB-device printer profile creation just records the gamut available in the target print. If the aim is to control ink limitations etc too then at least some ink reduction in the HP media preset is possible or another choice from the media presets can cover that. HP gives some ink limit numbers for different media presets and the ink channels used, totals so little is known about black generation etc. RGB-device printer profile creation does not take dotgain etc into account, it just measures the individual target patches and creates the available gamut. Your assumptions on dotgain etc might apply on CMYKetc profiling with access to ink limits, black generation etc.

As I understand it Mark looked for some proof in what the differences are between uncoated and coated stock in print quality and his aim to lay down the same ink limited amount of ink is correct. His choice of a Bristiol drawing paper is not the best though as that kind of paper has a strong sizing and often is calandered to create a smoother surface. The fact that the print "developed" is already an indication of that, ink medium fluids did not really separate from the pigment and the pigment could not really sink in the fibers. The softest, most open fiber, conventional art papers are the etching papers. Papers used for stone printing already have more sizing. The proofs I made on conventional Arches Velin show less gamut and more dotgain. Actually the Olmec OLM15 a 25% cotton inkjet paper already shows a lower gamut, Dmax, more ink spread, uneven color areas, due to a cheaper coating. So do Red River's matte inkjet papers. You can get very good inkjet papers, with excellent coatings, on different paper bases but a plain good paper base, excellent fiber quality is no guarantee for an excellent inkjet print.

A print on the back of a quality inkjet paper usually delivers a way worse print than using the side meant for printing. Dual sided and semi-dual sided inkjet papers not counted. Hundreds of printer users will agree on that, often to their shame. They will have done the test as objective as possible, with exactly the same settings as used for the print side and their observations not influenced by anything else than the expectation of a nice print. Test results often presented as naive as possible to a forum like this one.

BTW, which pigment ink have you let dry down to a powder in a container? It does not resemble my practical experiences with several ink types over time, nor does it fit well with pigment ink components described in documents. PoliVinylAlcohol already creates a bond and the pigment encapsulation is closer to a gel than a hard plastic and will certainly create a bond with PVA in the coating or the sizing. The encapsulation is also there to keep that particle suspended, sounds contrary to the other effect but the conditions in the ink medium differ from the conditions on the paper. A good explanation of methods to prevent flocculation can be found here:
http://www.inkline.gr/inkjet/newtech/tech/dispersion/  General, not specific for inkjet ink pigments but other articles will specify the encapsulation technology for inkjet ink pigment particles.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2016 update, 700+ inkjet media white spectral plots

[Mark Lindquist]

In response to Ernst's discussion, I have created targets on three different substrates that have no calendaring, no size, no chemical additives or processes to make the papers receptive to inkjet ink.

Since the Z3200ps creates patches that are based on the preset used, I made targets only without going into creating ICC profiles for the papers.  I doubt the ESP would make profiles anyway, since the papers all had very low white points.

The purpose of the test was to be able to observe the ink absorption of the paper and to test mainly for bleeding - one area or color into another.  As the test plainly shows, bleeding occurs only at a microscopic level, presumably, since little is visible to the naked eye.

Quality of print was expected to be very low, however, many of the colors, and most of the grays and blacks faired well.  The blacks well enough to actually print on with acceptable results, particularly with graphics.

I found an interesting quote from a thread back in 2013.

"Looks like various researchers have beaten me to it:

http://www.dp3project.org/preservation

Lots of useful articles there.

Bottom line: microporous layers crack very easily due to chemical as well as UV attack, and there's no easy way to restore them once they're cracked. The pigment inks which are printed on them are much more stable than the receptive layers themselves. According to micrographs, the paper base behind the microporous layer remains intact and undamaged. And sealing the back of a photo frame may not be the best idea after all.

I guess uncoated papers are the current solution for longevity after all. Now we just need to work out how to get inkjets to print on them better:

http://www.tappi.org/Downloads/Conference-Papers/2009/09PAPERCON/09pap33.aspx

Shadowblade - July 19, 2013, 11:49 AM..."

I don't mean to quote anything out of context, and please correct me if I have done so.  This statement, no doubt applies to off-gassing, yet does indicate some interesting points.

Throughout our discussions it has been stated that ink and carriers stay on the top levels above a barrier and do not go beneath into the paper itself.  It has also been stated that if the ink did go into the paper fibers, it would undoubtedly bleed and cause smearing or print degradation based on the inability of the paper (paper fibers) to hold the ink.

My test, albeit primitive and naive does indicate that uncoated papers can hold ink quite well and that the ink in fact does sink into the fibers of the paper and in so doing, does not bleed or smear.

I conclude that the receptors and coatings on Fine Art Matte are not all that there is to Matte papers.
Matte papers can stand almost on their own.  Why is it such a stretch to  imagine ink in fine art matte papers going down into the paper fiber base?

Anyway, Thanks everyone for humoring and indulging me.  However I did not expect quite such a guantlet.

Thanks to those of you who have been kind in refuting my idea.  Thanks to those of you who have attempted to understand what I'm getting at. 

I've learned a lot from this discussion and I appreciate everyone's involvement.

Mark

The first image is of the three papers I made targets on using Fine Art Papers - Fine Art More Ink 60 IL

The following three images are 100% crops of the 3 papers with labels.

All photos were taken with an i-Phone handheld, and no processing. - just cropping.

[Mark Lindquist]

Yes, I agree - it is an interesting discussion and reminds one that ink, paper and profiles are very critical variables in determining gamut and print quality, however defined. On the specific issue you raised about dry down time and print improvement over that period, not being an ink and paper chemist I cannot make any definitive statements about what really happens "under the hood", so this observation is empirical - i.e. based on what I see, and it is specific largely to several different PK papers printed in Epson 4900 or P800 printers using OEM inks and printer drivers mainly with custom icc profiles made in XRite software, so nothing exotic here. I find that I see some improvement in print clarity and shadow detail the morning after the night before, during which the prints are out-gassing in open air. The next morning I put them in archival storage boxes, the prints simply stacked. I went back to one of these boxes of prints I created some years ago, examined especially the backs of the prints, and saw no evidence of anything suggesting that chemical reactions having noticeable impacts were still occurring. So perhaps the real question is how much dry-down time is practically important; this experience for these materials would suggest about 12~24 hours.

Hi Again Mark.
Thanks for your reply, again.

Yes, I agree - 12-24 hours, then stability.

Best -

Mark

[Mark Lindquist]

I hesitate to get into the middle of one of these discussions, but FWIW, here are a few of my observations and what I've heard regarding a couple of the issues.

Printing on watercolor paper -- Arches Hot Press in particular -- can result in very good images, at least for black and white.  My QTR profiles go easy on the ink limits for the dilute inks, but heavy at the black end.  The Arches dmax is not reached until about 125% of the maximum QTR ink load.  So, I have 2 MK ink positions in my printers. 

The Arches smoothness will not be as good as a coated paper, but at "full sheet" (22x30 inches in the US) size, the normal viewer will not see the difference, and the critical viewer's appreciation of the underlying medium may offset the unevenness of some of the plain dark gray areas (like my heavily filtered skies). 

If the loose fibers on the top surface of Arches are likely to cause too many "shadows" (white spots) in these dark, plain areas, I suggest printing on the backside of the paper.  It has a texture I actually prefer in some respects. It seems to have fewer fibers sticking up off the surface.

BTW, remember to iron the deckle edges to avoid head strikes, and have fun figuring out how to deal with that deckle edge throwing off the printer's electric eye and image centering algorithms.

The advantages of a matte paper (any cotton based paper, probably) include that glycols have an "affinity" for cellulose and will likely just wrap themselves around those fibers and stay there, not outgas.  (This is according to a PhD chemist.)  The cellulose base, and particularly a cotton base, ends up taking care of much of the ink base products.  The barrier papers have a problem in this respect.

I have and am backing away from the very dilute gray inks used in many dedicated B&W inksets because, in part, I don't think we know what all those base chemicals are going to do in the long run.  Even in the short run, I see problems with putting too much water on the print.  Our medium has proved itself worthy at this point.  I no longer worry about people putting a loupe up to one of my prints and discovering that it is composed to tiny dots.  I rather agree with the OEM companies that the LLK density is about as light as we usually need.  After that, I wonder if the excess base chemicals are going to do more harm than good.

Paul
www.PaulRoark.com
http://www.paulroark.com/BW-Info/

Thank you Paul - good to know.  I like Arches...

Mark

[Mark Lindquist]

Unlike what happens in the wet darkroom, my understanding is that inkjet prints actually "dry up" very slightly rather than "dry down."  In other words, the print will be very slightly darker when it first comes off the printer compared to later after it has dried.  I've never actually measured this, but I think I've seen it visually, especially in the darker areas of the print.  I'm sure this probably varies (maybe a lot) depending on the ink and paper being used.

Dave

Thanks for participating in this discussion Dave -

Pretty much my observations as well.

Mark

[Mark Lindquist]

Regarding my post about a "barrier layer", it's being taken too literally as a total  moisture barrier. When ink jet papers are being coated, you need a base layer, commonly known as a "barrier" layer put down first to prepare the paper surface for subsequent coatings. Most inkjet papers have a number of coatings applied. There are several different ink jet receptor coatings also. Most common, today is the microporous receptor layer. In the early days of inkjet, attempts were made to print on all kinds of art papers. The most successful ones were "tub sized" papers using gelatin, most notably, Arches. (remember all traditional photo papers were coated with gelatin?) From this, modern ink jet paper coatings evolved. In any event, it is not desirable for the ink to penetrate into the base paper at all. As has been noted, the spectral qualities of ink jet ink come from the very top of the microporous layer. As ink drys, of course the image is subject to changes, just as a "wet pet rock" looks much different when it is viewed dry. (pardon the pet rock analogy)
The coatings are designed to prevent the "spread" of the ink droplet, preserving the small droplet size, and purity of the color.

Modern OEM pigmented ink has incorporated dispersants which function to keep the pigments from clumping and settling. They also have a "coating" agent like a polymer, that keeps the pigments strands separated, and also tends to create a contrasty look to the pigments (wet rock look), that enhances the d-max.

The water portion of the ink evaporates rather quickly, as has been noted. What takes longest, are the glycols, which can form a negative image film on a close-by glass surface. Most of the "dry down" is within 24 hours depending on ambient conditions. The glycols of course take much longer.


John Nollendorfs

Hi John -
Thanks for participating - appreciate your info and impressions.

Mark

[Mark Lindquist]

A further test.  I folded and soaked paper towel and rubbed each printed example aggressively to see if the ink did penetrate deeply into the fibers.

I was surprised at the results.  The paper which I expected to do the worst, (the paper mill blotter type paper) was unfazed.  It kept drinking and soaking up the water like a sponge and the inks were largely unfazed as well.

Notice the wet paper towel in the paper mill blotter type paper.  Very little ink came off after a lot of scrubbing.  The more water I put on the tougher it became.

In each case, however, the test demonstrates that the ink did penetrate into the fibers and is relatively strong.  Strong enough to withstand serious scrubbing. 

Any surface coating would have long since been scrubbed away.

Mark