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Author Topic: Are there any 100% cotton glossy/luster papers without TiO2?  (Read 4226 times)

mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #20 on: July 27, 2019, 06:37:07 pm »

I think this is a little more complicated.  I just took a look at the paper by the French scientists.  Yes, there is formation of ozone but the paper I'm reading notes that it requires a clear surface of TiO2 for the reaction to take place.  They used glass plates coated with TiO2 and exposed the plate to a synthetic atmosphere.  They used near UV light in one test and sunlight in a second.  It's important to note that TiO2 is the bottom layer in inkjet paper, coating the paper base and the ink receptive surface is on top of that.  I'm unsure what the level of nitrogen oxides are in a typical indoor viewing environment but it may not be high enough to matter much.  In addition, the illumination source may not have enough energy at the surface to make a big difference.  All this being said, there is a risk in using TiO2 coated inkjet paper in terms of print permanence.  As to how much color degradation will take place and over what time period remains to be determined.  If you are concerned about long term stability of inkjet prints it is advisable to avoid such papers.
After all the problems Ctein had I see no reason to take any chance with any papers that contain TiO2 especially when there are viable alternatives.

As an example, I called BC and asked about their new 100% cotton paper River Stone Satin Rag and was told it did contain TiO2.  Now I no longer have any interest in testing it, so this information save me both time and money.
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deanwork

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #21 on: July 27, 2019, 08:29:20 pm »

I certainly don’t want to speak for Mark, especially since he is still evaluating these issues with little or no budget to do so and we are lucky to know anything, but I believe he told me that the heat melting of the thermoplastic tissue releases BHT that can react with other airborne chemicals to produce staining.

Cold pressure adhesive mounting seems to be safer IF it doesn’t contain problematic chemicals as in preservatives, etc. I have talked to many higher-end mounting specialists, even the big ones in NY, and I can’t find anyone who will tell me what actually is in their adhesives and what their longevity characteristics are.  The only thing they will ever tell you is that they are “acid free” because that is what the manufacturers tell them.

I have many Platine prints that I have drymounted to 8 ply rag board with Seal tissue, and none of them have discolored. But the oldest are only a few years old.

John




Ouch Mark, I hadn't thought of dry mount tissues as a source of contamination. So what do you use instead to hold the print flat?
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #22 on: July 27, 2019, 09:50:24 pm »

I certainly don’t want to speak for Mark, especially since he is still evaluating these issues with little or no budget to do so and we are lucky to know anything, but I believe he told me that the heat melting of the thermoplastic tissue releases BHT that can react with other airborne chemicals to produce staining.

Cold pressure adhesive mounting seems to be safer IF it doesn’t contain problematic chemicals as in preservatives, etc. I have talked to many higher-end mounting specialists, even the big ones in NY, and I can’t find anyone who will tell me what actually is in their adhesives and what their longevity characteristics are.  The only thing they will ever tell you is that they are “acid free” because that is what the manufacturers tell them.

I have many Platine prints that I have drymounted to 8 ply rag board with Seal tissue, and none of them have discolored. But the oldest are only a few years old.

John
Thanks John, there's still so much we don't know about archivability.
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Alan Goldhammer

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #23 on: July 28, 2019, 08:13:24 am »

Ouch Mark, I hadn't thought of dry mount tissues as a source of contamination. So what do you use instead to hold the print flat?
When I was still doing dry mounting of photos I used Fusion 4000 which is a low temperature dry mount tissue.  I don't know what the thermoplastic they use to make it as I can't find a specification sheet.  I still have some traditional B/W photos that have been mounted with this material from back in the early 1980s and those show no degradation.  Mark is likely correct that inkjet media pose new issues for conservationists to study.

To answer your question about mounting, I can only tell you how I approach the issue.  For papers up to 17x22 (I don't print on rolls so that's the largest size for me), I leave a one inch border on all sides.  I use Mylar photo corners on foam board and cut the overmat so that it completely covers the unprinted border.  I use Nielsen frames with enough springs on the back to make sure the print is firmly fixed.  Last summer I went back to an office installation where about 16 prints have been hanging for 11 years to check on how the colors were holding up (standard office illumination on for about 14 hours a day).  They still looked good and I did not see any buckling or waviness in the prints.  They were all 13x19 inch prints in 16x20 inch frames.  I used standard acrylic glazing.
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MHMG

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #24 on: July 28, 2019, 10:26:52 am »

Ouch Mark, I hadn't thought of dry mount tissues as a source of contamination. So what do you use instead to hold the print flat?

I have evolved to an adhesive-free style of mounting/framing for my personal work. Would be easier to show in a video sometime, but I'll try to provide some insight with a modest verbal description here.

First I prefer the beauty of wood frame for my work, so I use wood frames, the caveat being to seal the rabbets with frame sealing tape (e.g. Lineco frame sealing tape). This tape looks like a white paper tape, but it has an internal aluminum foil carrier, so it isolates both the wood and even its own adhesive from the print, mount board and overmatte when used.  It eliminates any concern about off gassing from the wood discoloring the edges of the print.

Second, I print with wide margins or trim borderless when I want a borderless look. For my borderless prints, I print on a matte fine art paper such as Moab Entrada  natural 300gsm. Framers all advise that placing a photograph in direct contact with glazing is bad practice, but they learned this from experience with silver gelatin prints. Gelatin is gelatin which means at moderately high humidity (70%RH which is a very real world result in many regions of the world) it reverts to gel state. then as humidity drops it blocks and sticks to the glass. However, a fine art Matte paper like Moab Entrada does not have a gelatin binder and the microporous silica in its binder acts as an anti-blocking layer to prevent the well known "ferrotyping" issue with traditional photos. Hence, placing the matte fine art media in direct contact with the glazing is a totally safe practice in my situation, and in fact it gives the print nearly the same visual "pop" that folks get with other face mounted acrylic print methods yet retains total reversibility. If the acrylic scratches, simply disassemble the piece, remove the print and replace the acrylic.

Third, I add a 2 ply conservation matte/mound board behind the print to serve as additional moisture buffering material in the framed print's microclimate environment. Then I lay in an oversized 1/16 inch PE foam liner sheet into the frame followed by a conservation grade foam board and finish off with framing points. Then the excess PE foam is easily trimmed with a utility knife (cuts like butter). The PE foam is doing a couple of things. It is first and foremost a vapor barrier, not a perfect one, but good enough to stabilize the microclimate in the frame to mitigate daily/weekly/monthly RH swings which when severe enough contribute to cockling of some artwork on paper over time. It is also a dust jacket but hidden underneath the foam core board rather than placed on the back of the frame (I can't tell you how many torn dust jackets on the back of frames I've seen over the years, my approach avoids that problem). Lastly it cushions the print and Matt board assembly to even out any pressure points in the package and thus helps to ensure the print expands and contracts uniformly over long periods of seasonal RH cycles.

For my prints where I want an overmatte, I simply print a wide margin border (e.g., 2.5, 3, 4 or more inches of margin around the image) such that the final print size matches the overmatte, mount board, and frame's inner dimensions. This eliminates the time-consuming practice of T-hinging, corner mounting, etc and gets rid of any adhesives inside the framed print microclimate. One just inserts the glazing into the frame, then the overmatte when used, then the  print, then the 2 or 4 ply mount board, then drop in the PE foam layer, finally the foam core backer board, and finish off with framing points.  I concede my technique of wide margins lends itself to 24 and 44 inch printers better than the smaller prosumer desktop models, but the time and labor savings are tremendous, i.e., worth it to consider stepping up to a 24 inch printer over a 17 inch desktop model. I often print the image with a fine stroke line which shows where to cut, and then the image, and the overmatte, mounting, and frame components all self align..not tedious measurements to get image and overmatte looking perfectly centered.

I've used this approach to framing my work for several years, and so far so good. I also routinely print at up to 32x40, so I can confirm my method works well up to that size. I don't have any need to go bigger with my personal work, but I'd guess the technique could be adapted to larger pieces, perhaps going to a stiffer backing board, slightly thicker PE foam, and a thicker acrylic glazing sheet for larger pieces.

I hope that describes how I avoid adhesive mounting techniques entirely when printing and framing fine art inkjet papers.

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

« Last Edit: July 28, 2019, 11:00:24 am by MHMG »
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #25 on: July 28, 2019, 11:00:45 am »

I have evolved to an adhesive-free style of mounting/framing for my personal work. Would be easier to show in a video sometime, but I'll try to provide some insight with a modest verbal description here.

First I prefer the beauty of wood frame for my work, so I use wood frames, the caveat being to seal the rabbets with frame sealing tape (e.g. Lineco frame sealing tape). This tape looks like a white paper tape, but it has an internal aluminum foil carrier, so it isolates both the wood and even its own adhesive from the print, mount board and overmatte when used.  It eliminates any concern about off gassing from the wood discoloring the edges of the print.

Second, I print with wide margins or trim borderless when I want a borderless look. For my borderless prints, I print on a matte fine art paper such as Moab Entrada  natural 300gsm. Framers all advise that placing a photograph in direct contact with glazing is bad practice, but they learned this from experience with silver gelatin prints. Gelatin is gelatin which means at moderately high humidity (70%RH which is a very real world result in many regions of the world) it reverts to gel state. then as humidity drops it blocks and sticks to the glass. However, a fine are Matte paper like Moab Entrada does not have a gelatin binder and the microporous silica in its binder acts as an anti-blocking layer to prevent the well known "ferrotyping" issue with traditional photos. Hence, placing the matte fine art media in direct contact with the glazing is a totally safe practice in my situation, and in fact it gives the print nearly the same visual "pop" and that folks get with other face mounted acrylic print methods yet retains total reversibility. If the acrylic scratches, simply disassemble the piece, remove the print and replace the acrylic.

Third, I add a 2 ply conservation matte/mound board behind the print to serve as a moisture buffering material in the framed print's microclimate environment. Then I lay in an oversized 1/16 inch PE foam liner sheet into the frame followed by a conservation grade foam board and finish off with framing points. Then the excess PE foam is easily trimmed with a utility knife (cuts like butter). The PE foam is doing a couple of things. It is first and foremost a vapor barrier, not a perfect one, but good enough to stabilize the microclimate in the frame to mitigate daily/weekly/monthly RH swings which when severe enough contribute to cockling of some artwork on paper over time. It is also a dust jacket but hidden underneath the foam core board rather than placed on the back of the frame (I can't tell you how many torn dust jackets on the back of frames I've seen over the years, my approach avoids that problem). Lastly it cushions the print and Matt board assembly to even out any pressure points in the package and thus helps to ensure the print expands and contracts uniformly over long periods of seasonal RH cycles.

For my prints where I want an overmatte, I simply print a wide margin border (e.g., 2.5, 3, 4 or more inches of margin around the image) such that the final print size matches the overmatte, mount board, and frame's inner dimensions. This eliminates the time-consuming practice of T-hinging, corner mounting, etc and gets rid of any adhesives inside the framed print microclimate. One just inserts the glazing into the frame, then the overmatte when used, then the  print, then the 2 or 4 ply mount board, then drop in the PE foam layer, finally the foam core backer board, and finish off with framing points.  I concede my technique of wide margins lends itself to 24 and 44 inch printers better than the smaller prosumer desktop models, but the time and labor savings are tremendous, i.e., worth it to consider stepping up to a 24 inch printer over a 17 inch desktop model. I often print the image with a fine stroke line which shows where to cut, and then the image, and the overmatte, mounting, and frame components all self align..not tedious measurements to get image and overmatte looking perfectly centered.

I've used this approach to framing my work for several years, and so far so good. I also routinely print at up to 32x40, so I can confirm my method works well up to that size. I don't have any need to go bigger with my personal work, but I'd guess the technique could be adapted to larger pieces, perhaps going to a stiffer backing board, slightly thicker PE foam, and a thicker acrylic glazing sheet for larger pieces.

I hope that describes how I avoid adhesive mounting techniques entirely when printing and framing fine art inkjet papers.

cheers,
Mark
http://www.aardenburg-imaging.com
Great information Mark, thank you. It's nice to know that the glazing can touch the print without damage. But does this hold true for the Photo Rag Pearl you recommended as well? Since most of my work is color, my concern is a loss of color saturation and dmax if I use a matte paper.   
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MHMG

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #26 on: July 28, 2019, 11:55:35 am »

Great information Mark, thank you. It's nice to know that the glazing can touch the print without damage. But does this hold true for the Photo Rag Pearl you recommended as well? Since most of my work is color, my concern is a loss of color saturation and dmax if I use a matte paper.

Well, you are certainly safe using gloss/luster media with my wide margin technique and an overmatte to give the traditional air gap, but if truth be told, I've used HN Ph Rag Pearl in borderless configurations as well, and so far so good after several years on display. The only caveat here, is that I spray the HN PH Rag Pearl with a couple of coats of Premier Print shield (or you can use HN protective spray, Moab desert varnish with equal results). This spraying step is a PITA, but it eliminates all bronzing and differential gloss, plus it seals the print surface with a thin and conformal acrylic polymer layer which should be fine against the glazing.

There's no question it takes more image editing care and skill to get great color and tonality with a fine art matte paper compared to printing on glossy/luster media, but the final results under glazing are rather amazing and surprising. With glossy/luster media the viewer really needs to be at a near normal viewing angle to achieve the high Dmax look. The richness tends to fall of noticeably with off-angle viewing. However, with matte fine art papers, the print viewing angle is much more tolerant of off-axis viewing, and the glazing really does impart to the matte papers far more "pop" and richness of the blacks in the image than the physics/optics of 0/45 spectrophotometer measurements actually account for.  Hence, I started out using more HN Photo Rag Pearl than Moab Entrada Natural when I first worked out my printing/framing methods, but now almost all of my work is on the Entrada Natural 300gsm.

cheers,
Mark
« Last Edit: July 28, 2019, 04:07:42 pm by MHMG »
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deanwork

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #27 on: July 28, 2019, 12:19:18 pm »

It’s interesting that you do that Mark.

About a year ago I started suggesting to clients that framing with prints touching the plexi inside a frame with acid free foamcor or rag board ( better) backing is a much cheaper and viable option for the duration of a show. You avoid the expense of mounting to dibond and all that weight added, or mounting with some questionable substrate like Sinatra or the most common bad choice Gator Board. I can’t tell you how many beautiful big prints I’ve done were mounted by clients to gator. I hate to think about it.

In my experience this method has been very successful. I have had four 30x40 ish prints hanging in my home framed in wooden frames this way for 15 years, mostly matte rag media and sprayed with Premiere Art uv varnish and they are in perfect condition, exposed to daylight every day. I thought I would have to replace them in a year but I never did. One had a moth creep inside it but it wasn’t well sealed on the back, that’s important. 🙂 I have three Platine prints in the 20x30 size framed this way that still look perfect for 3 years. I don’t have a lot of humidity in my house and studio however. That could be a huge issue it seems to me, but maybe they could be perfectly sealed to keep moisture out.

Having said all that I’m still reluctant to tell galleries to SELL prints framed this way for permanent display. I might change my mind though as we learn more. I also don’t know if this method would work for 40x60 and larger  prints, pressed against the glass like that. I’m pretty sure rc prints would be fine but matte cotton prints may ripple some, without some kind of internal bracing ....don’t know. I need to try it though.
Too many things to think about. I wish the big museums would put some resources into studying these display issues. If they have I haven’t heard about it.

John





Great information Mark, thank you. It's nice to know that the glazing can touch the print without damage. But does this hold true for the Photo Rag Pearl you recommended as well? Since most of my work is color, my concern is a loss of color saturation and dmax if I use a matte paper.
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movergaard

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #28 on: July 28, 2019, 01:03:35 pm »

As usual, Mark, an extremely helpful post.  Thanks!

My question: what are the UV considerations for your approach?  With Entrada Natural, do you consider it necessary to use glazing that includes UV protection or apply a spray that includes that protection?

Mark
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stockjock

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #29 on: July 28, 2019, 01:48:42 pm »

Great post Mark.  Can you provide a source for the PE foam liner sheets you use? 

Thanks.

Paul
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #30 on: July 28, 2019, 01:54:30 pm »

Well, you are certainly safe using gloss/luster media with my wide margin technique and an overmatte to give the traditional air gap, but if truth be told, I've used HN Ph Rag Pearl in borderless configurations as well, and so far so good after several years on display. The only caveat here, is that I spray the HN PH Rag Pearl with a couple of coats of Premier Print shield (or you can use HN protective spray, Moab desert varnish with equal results). This spraying step is a PITA, but it eliminates all bronzing and differential gloss, plus it seals the print surface with a thin and conformal acrylic polymer layer which should be fine against the glazing.

There's no question it takes more image editing care and skill to get great color and tonality with a fine art matte paper compared to printing on glossy/luster media, but the final results under glazing are rather amazing and surprising. With glossy/luster media the viewer really needs to be at a near normal viewing angle to achieve the high Dmax look. The richness tends to fall of noticeably with off-angle viewing. However, with matte fine art papers, the print viewing angle is much more tolerant off off axis viewing, and the glazing really does impart to the matte papers far more "pop" and richness of the blacks in the image than the physics/optics of 0/45 spectrophotometer measurements actually account for.  Hence, I started out using more HN Photo Rag Pearl than Moab Entrada Natural when I first worked out my printing/framing methods, but now almost all of my work is on the Entrada Natural 300gsm.

cheers,
Mark
More good info Mark, thanks again. I'll have to try that.
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #31 on: July 28, 2019, 01:56:31 pm »

It’s interesting that you do that Mark.

About a year ago I started suggesting to clients that framing with prints touching the plexi inside a frame with acid free foamcor or rag board ( better) backing is a much cheaper and viable option for the duration of a show. You avoid the expense of mounting to dibond and all that weight added, or mounting with some questionable substrate like Sinatra or the most common bad choice Gator Board. I can’t tell you how many beautiful big prints I’ve done were mounted by clients to gator. I hate to think about it.


John
So what's wrong with Gatorboard? I thought it was a favorite since it doesn't warp.
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #32 on: July 28, 2019, 02:10:51 pm »

Mark, one more question. Why the Moab 300gsm double sided instead of the 290gsm single sided?
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deanwork

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #33 on: July 28, 2019, 02:17:40 pm »

One thing is it’s highly acidic and not good for cotton media.

 Gatorfoam is not recommended for archival framing as the make-up is polystyrene foam sandwiched between two sheets of wood-fiber veneer which contains a formaldehyde-releasing chemical. It also dents easily and unlike dibond or 8 ply rag board, has to be handled with extreme care. It may be rigid but it is still soft on the surface.




So what's wrong with Gatorboard? I thought it was a favorite since it doesn't warp.
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Alan Goldhammer

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #34 on: July 28, 2019, 03:40:20 pm »

Mark, one more question. Why the Moab 300gsm double sided instead of the 290gsm single sided?
Not Mark, but have an answer anyway.  290gsm is only available in rolls.  For those of us who use Entrada and don't have a printer that can use roll paper we use the double sided 300gsm cut sheets.
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MHMG

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #35 on: July 28, 2019, 03:45:51 pm »

Great post Mark.  Can you provide a source for the PE foam liner sheets you use? 

Thanks.

Paul

Uline
Uline is where I get it. I'm guessing folks overseas have similar suppliers as Uline. You do have to buy in 1 or 2 roll minimum (the rolls are over 1000 ft long, and pretty bulky), but PE foam has many other uses and is dirt cheap per linear foot.  For example, I place it on top of the printed image as a super soft interleaving sheet when I decurl prints. Keeps surface perfectly free of fine abrasion/scuffing that matte prints seem to be very sensitive to. I also place it on my work table before laying down acrylic glazing to clean it. You can handle the acrylic with absolutely no worries about scratching. I will also use it as temporary interleaving for ink jet prints when rolling onto a tube for shipping (I roll print on outside of tube, then package the tube in a cardboard box designed just for the tube length and diameter. The recipient gets a print that is much easier to remove from the tube without potential damage compared to putting the print inside the tube.

Only cautionary tale I have for PE foam is I don't it use for long term storage in direct contact with paintings or furniture pieces which have natural resin varnishes like shellac. These varnishes can start to conform to the texture of the PE over time if temperature gets somewhat elevated and there is some pressure on the PE foam, but in the framing situation I described earlier for my personal fine art printmaking, the PE foam is behind the 2(or 4) ply matt board, thus between the Matt board back and the foam core. Never touches the front or back of the print.

cheers,
Mark
« Last Edit: July 28, 2019, 05:14:53 pm by MHMG »
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mearussi

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #36 on: July 28, 2019, 03:51:00 pm »

Not Mark, but have an answer anyway.  290gsm is only available in rolls.  For those of us who use Entrada and don't have a printer that can use roll paper we use the double sided 300gsm cut sheets.
Makes sense, but I use 24" rolls for most of my work.
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MHMG

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #37 on: July 28, 2019, 03:57:01 pm »

Mark, one more question. Why the Moab 300gsm double sided instead of the 290gsm single sided?

the 290 single sided version would work fine, but I prefer the 300gsm dual sided roll version for two reasons. First, I back print lot's of metadata including my personal stamps, camera data, gps data, date photographed and date printed, printer/ink/media info all on the verso. It's also where I sign in pencil (Moab Entrada coatings take #2 pencil beautifully). It becomes my personal time capsule. When folks clean or reframe in the future, none of the info will get lost. It will stay with the print as long as the print survives. The opacity of the dual sided 300gsm is so good, than none of this back printing "ghosts" through to the image on the front side.

Second, even the best printmakers  ::) among us create some reject prints from time to time. I repurpose those reject prints for new proof prints using the unprinted verso. The coated back side is the perfect "proofing" paper since the coating is the same both sides 8) Thus, I actually find in the long run, the 300gsm dual sided is less expensive to stock in house than the 290gsm single sided Entrada.

cheers,
Mark
http://www.aardenburg-imaging.com
« Last Edit: July 28, 2019, 04:04:29 pm by MHMG »
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MHMG

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #38 on: July 28, 2019, 04:51:28 pm »

As usual, Mark, an extremely helpful post.  Thanks!

My question: what are the UV considerations for your approach?  With Entrada Natural, do you consider it necessary to use glazing that includes UV protection or apply a spray that includes that protection?

Mark

There's a great deal of UV mythology out there in conservation framing land, IMHO. It may sound like heresy, but I don't even worry about UV blocking properties of the glazing nor do I believe thin top coatings on the print itself add any significant UV protection (although they may have other benefits). I base my opinion on some scientific facts.

1) All the UV blocking versus no UV blocking studies I have ever read return similar fading results. Full UV cut protection typically results in lower fade rates by 2-3x in the many studies which have been done, with some very sensitive colorants maybe benefitting by as much as 5x. However, my advice to print collectors is before you worry about potential 2-3x or even 5x fade reduction by buying expensive museum glass or the like, by an inexpensive lux meter or lux datalogger (Onset Computer Corporation makes a nice bluetooth lux and temperature datalogger for about $75) and use your light meter to take a cold hard look at your actual lighting and display conditions.  A lot of UV attenuation is taking place on the walls, floors and ceilings of the room (latex paint contains an excellent UV absorber, wait for it, it's TiO2), and the remaining UV energy is always proportional to the visible light energy (Lux). So, unless you are allowing direct sunlight to strike the print, the 2-3x reduction factor probably isn't going to be realized over time.  Second, because the UV component in the spectrum is always proportional in some linear way to the visible light energy coming from the same light source, tracking the visible light intensity also correlates very well with the fading danger posed to the print by the light source. Follow the light intensity! 100x higher light level will lead to roughly 100x faster fade rate! The typical room-to-room variation from lowest real world illumination levels for prints on display compared to highest illumination levels on display is almost always 10x to 100x and sometimes even greater than 1000x. This reality can be true even in just one room. Hence, if you had two identical prints located in the same room, one with UV blocking glazing and the other with regular glass, then merely by relocating the glass covered one to a less illuminated wall could easily get it to outlast the UV blocked version hanging in a higher illuminated area perhaps only a few feet away.  Moral of the story: Pay attention to illumination levels on display. It's why Aardenburg posts its conservation display ratings as exposure values (Megalux hours) which are a product of both light intensity and time, rather than assuming an average "one-size-fits-all light level" for all prints on display in order to simplify (oversimplify) the print longevity ratings to "years on display".  Such a single light level assumption leads to print longevity ratings that can be ludicrously far off from what the print collector will experience in real life.  Light intensity, not UV content is the elephant in the room!!!

Lastly, museums usually kill the UV energy debate right at the light source. Modern high CRI LED lamps, for example, are pretty much UV-free.  Cheaper to do that than to keep framing prints under expensive museum glass or OP3 plexiglass which can also impart unwanted color to the images on display.

Again, I know I'm going against the prevailing framing industry wisdom by saying this stuff, but if you sell or give your work to others where you have no control on how they display them, then this light level discussion is the important discussion to have with them. Don't shoot the messenger :)

kind regards,
Mark
http://www.aardenburg-imaging.com
« Last Edit: July 28, 2019, 05:06:52 pm by MHMG »
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movergaard

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Re: Are there any 100% cotton glossy/luster papers without TiO2?
« Reply #39 on: July 28, 2019, 07:20:42 pm »

There's a great deal of UV mythology out there in conservation framing land, IMHO. It may sound like heresy, but I don't even worry about UV blocking properties of the glazing nor do I believe thin top coatings on the print itself add any significant UV protection (although they may have other benefits). I base my opinion on some scientific facts.

Another highly useful post, Mark.  Thanks, again.  No further questions right now.

Mark
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