I wonder just how toxic Eco Print Shield and the like are.

[Alan Goldhammer]

Premier implies the protective benefit is largely due to UV blockers in the spray, but I really doubt that. Even with three or four coats applied, the final coating is too thin to filter out much UVA radiation. Normal glazing like ordinary picture frame glass filters out the UVB/UVC rays, so evaluating UVA radiation attenuation is the key this product claim. Try an experiment with Print Shield on an an OBA-rich paper like Epson Exhibition Fiber. Cover half the paper and spray. Then look at the paper under blacklight. If the coating was a  highly effective UV blocker, the coated side wouldn't glow under blacklight. But it does...almost as much as the non sprayed side. So, what's going on here? By sealing the pores, the light-induced and ozone-induced oxidation rate of the colorants is being significantly reduced because the surface area-to-volume ratio of the microporous ink receptor coating is being radically altered.  In AaI&A tests and those done by WIR, fade resistance can nearly double when Print Shield (also, re-badged as HN Protective Spray, etc) is used. And equally important, the image layer now has much better scratch and abrasion resistance, so it's a win-win for durability despite being a total PITA to use and expensive as well.

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

Mark, what they are saying is only part true as the experiment with EEF shows.  They can make claims about reducing UV but in reality it doesn't eliminate all the UV rays hitting the print as you have observed.  I've seen plain acrylic glazing advertised by some vendors as being UV protecting for the same reason.  I suspect that the real protection afforded by these sprays is sealing the image face so that atmospheric pollutants don't get to the print surface and impact fading.

Alan

[MHMG]

Mark, what they are saying is only part true as the experiment with EEF shows.  They can make claims about reducing UV but in reality it doesn't eliminate all the UV rays hitting the print as you have observed.  I've seen plain acrylic glazing advertised by some vendors as being UV protecting for the same reason.  I suspect that the real protection afforded by these sprays is sealing the image face so that atmospheric pollutants don't get to the print surface and impact fading.

Alan

Right, standard acrylic has a strong cut off below about 360 nm and partial at 370nm, so it does still transmit a good portion of UVA radiation between 375 and 390 nm. But when you try my blacklight test you will still see that standard acrylic does provide significant UV reduction. Not nearly so with thin coats of Print Shield.  For an illustration of the UV blocking effectiveness of standard and OP3 (full UV block) acrylic versus ordinary glass  see figure 4 in the following article:

http://www.aardenburg-imaging.com/news.18.html

cheers,
Mark

[MHMG]

Mark, I have been experimenting with coating cotton rag papers (e.g. Canson Rag Photographique) with Breathing Color Timeless for display in a frame without glass. If I understand your comments correctly, your concern is with the impact Timeless (or a similar product) has on the aesthetic of the paper, rather than a concern about an impact on the stability of the paper itself. Am I correct?

What are your thoughts on using Renaissance Wax to achieve the same result?

Terry.

If you like the aesthetic of a heavier "varnish" coating on traditional photo surfaces, go for it. Nothing wrong with that.  As for Timeless (or similar product) impact on stability, I think the only way to really know with more certainty is to specifically test it.

I had read about artists using Renaissance Micro-crystalline Wax on Inkjet prints, so I ordered a jar. Very interesting. It's widely used in conservation but mainly as a protective finish for metal objects, also some use on wooden objects. There is also some historic use of waxes on traditional photographic prints (including platinum/palladium print with various long term outcomes both good and bad), but as for sealing microporous inkjet receptor coatings, I think it's a real wildcard.  We need to do some testing, and I hope to put some wax coated print samples into test this year. So much to do..so little time ;-)  That said, I have already seen one disturbing result on a couple RC based inkjet papers I tried coating. The wax darkens the media white point considerably. Can't explain the result as merely a light transmission issue.  This darkening doesn't happen to all papers, just some, so there is definitely some compatibility issues with this wax and some inkjet coating formulations.

[Alan Goldhammer]

Right, standard acrylic has a strong cut off below about 360 nm and partial at 370nm, so it does still transmit a good portion of UVA radiation between 375 and 390 nm. But when you try my blacklight test you will still see that standard acrylic does provide significant UV reduction. Not nearly so with thin coats of Print Shield.  For an illustration of the UV blocking effectiveness of standard and OP3 (full UV block) acrylic versus ordinary glass  see figure 4 in the following article:

http://www.aardenburg-imaging.com/news.18.html

cheers,
Mark

Mark, am I correct in observing that the OP3 acrylic warms the paper white of the Museo Silver Rag?  Sure looks like it.

Alan

[tim wolcott]

I just sprayed 205 large prints for my Texas project.  I would not be using it if it was toxic.  And yes when spraying that many you will get it on you no matter just how good of a spryer you think you are.  You have no worries and you should have taken it out when it landed.  I usually have some tools there when spraying to make sure if something happens I can get it out quickly and proceed on.  As coach Wooden said "Failure to prepare is preparing to fail."  T

[MHMG]

Mark, am I correct in observing that the OP3 acrylic warms the paper white of the Museo Silver Rag?  Sure looks like it.

Alan

Yes, the full UV block glazings are generally sharp cutting right at 400nm, but do absorb a little into higher blue wavelength region as well, so they can add a very slight yellowishness to the viewing condition. This nature of OP3 has to do only with the transmission characteristics of the glazing, not whether the print has OBAs to fluoresce or not.   Some people are OK with the slight yellowish tint that OP3 imparts, others not. If it is bothersome, standard acrylic is the middle ground for UV absorption/transmission, between full UV-cut glazing and plain glass in UV transmission performance, and is usually more optically clear than even glass which sometimes adds a slight greenish tint.

[Alan Goldhammer]

Yes, the full UV block glazings are generally sharp cutting right at 400nm, but do absorb a little into higher blue wavelength region as well, so they can add a very slight yellowishness to the viewing condition. This nature of OP3 has to do only with the transmission characteristics of the glazing, not whether the print has OBAs to fluoresce or not.   Some people are OK with the slight yellowish tint that OP3 imparts, others not. If it is bothersome, standard acrylic is the middle ground for UV absorption/transmission, between full UV-cut glazing and plain glass in UV transmission performance, and is usually more optically clear than even glass which sometimes adds a slight greenish tint.

Thanks.  Standard acrylic is also quite a bit cheaper than OP3 or comparable other UV blocking acrylics.

[Ernst Dinkla]

While I wouldn't go so far as to suggest these aqueous-based coatings will eat through the print, I have seen notable field failures of coated canvas (sent to me by AaI&A members) that can't be explained merely by intense light fading issues. Also, in one paired comparison test (coated versus uncoated canvas print samples with K3 Ultrachrome inks) currently undergoing lightfastness testing at AaI&A the uncoated print sample is faring better in test than the coated sample. That said, the solvent based coatings like Premier Print Shield seem to consistently improve print durability (lightfastness, gas fastness) but they are mainly used with matte papers and glossy photo type papers (they basically are too brittle a coating to remain crack free with canvas stretching).

My overall sense is that there are potential compatibility issues that need further research. Some canvas/coating combinations will no doubt be excellent while others will lead to additional print permanence problems down the road. The chemistry of the ink receptor layer of the canvas product is likely to be a major variable.

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

Aqueous acrylic varnishes are disperged emulsions and it is correct that the created film is not that gas tight etc as a similar solvent based film. Depending on the amount of varnish applied that could make a difference but I wonder whether the observation isn't also related to the spraying method. With aqueous coatings and HVLP guns it is possible to apply thick varnish emulsions that do not penetrate the inkjet coating but stay on top. I prefer to use more diluted acrylics in three layers, forced drying in between. The first layer doesn't build a coat but is absorbed in the layer. My thoughts were that that way the varnish would add to the mechanical bond of the inkjet coating and encapsulate the pigment better.

BTW, I used a simple wax on the HP Baryte paper to correct an issue with that paper. Renaissance wax should do better. The paper creates a fog like outer surface with the Vivera pigment ink that lowers Dmax etc. Whether the gloss enhancer is used or not. Though I prefer HM Barytra Rag I can use the HP Baryta if I print without GE, let the print dry and gently polish the top first with a woollen cloth and then apply the wax with another cloth. It restores the Dmax and there is no visible change in the paper white of the HP Baryta. From a conservation perspective wax is an interesting coating medium. Encaustic painting dates back to 500 BC. Wooden ships were coated with wax, beewax or wax-resin from trees. For inkjet printing it has been used in the First system, special vinyl media with an inkjet coating that could be printed on for example Novajets and then cured through an oven which embedded  the inkjet coating and ink in the wax/resin layer underneath the inkjet coating. At least that is what I did understand of that process. I can not find any reference to that system anymore.


met vriendelijke groeten, Ernst Dinkla

Dinkla Gallery Canvas Wrap Actions for Photoshop
http://www.pigment-print.com/dinklacanvaswraps/index.html

[Alan Goldhammer]

Aqueous acrylic varnishes are disperged emulsions and it is correct that the created film is not that gas tight etc as a similar solvent based film. Depending on the amount of varnish applied that could make a difference but I wonder whether the observation isn't also related to the spraying method. With aqueous coatings and HVLP guns it is possible to apply thick varnish emulsions that do not penetrate the inkjet coating but stay on top. I prefer to use more diluted acrylics in three layers, forced drying in between. The first layer doesn't build a coat but is absorbed in the layer. My thoughts were that that way the varnish would add to the mechanical bond of the inkjet coating and encapsulate the pigment better.

Ernst, I think this is all going to be dependent on the size of the resin particles versus the pore size in the paper coating.  I'm not sure how much is publicly known about either since they may be trade secrets of the manufacturers.  A lot of years ago when I was still doing bench biochemistry I did a lot of polyacrylamide gel electrophoresis and one could control the polymerization rates and also the physical properties of the gel itself.  This is different because the acrylate is a solid rather than a gel and controlling polymerization is likely to be quite different.  For the micro-porus papers such as Ilford GFS, my presumption is that the film stays on top and seals over the image.  You are probably correct that a solvent based spray will give different film properties (but depending on the solvent may raise worker exposure issues which is why water based products are preferred).

[Ernst Dinkla]

Ernst, I think this is all going to be dependent on the size of the resin particles versus the pore size in the paper coating.  I'm not sure how much is publicly known about either since they may be trade secrets of the manufacturers.  A lot of years ago when I was still doing bench biochemistry I did a lot of polyacrylamide gel electrophoresis and one could control the polymerization rates and also the physical properties of the gel itself.  This is different because the acrylate is a solid rather than a gel and controlling polymerization is likely to be quite different.  For the micro-porus papers such as Ilford GFS, my presumption is that the film stays on top and seals over the image.  You are probably correct that a solvent based spray will give different film properties (but depending on the solvent may raise worker exposure issues which is why water based products are preferred).

You are right. Another one to add, the resin particle size. I have used the Lascaux 2060 varnish diluted 1:1 on canvas coating and like I wrote I think the coating absorbs the first layer, there's no gloss buiding then. The second layer does.

With several protective sprays from the can (solvent based) I observed something similar on PhotoRag. Some qualities do not penetrate the coating and change the matte surface, black especially, usually uneven. HM and Premier are known to act good.  There was a quality "Giant" that had less of that effect and the Talens Protective Spray 680, acrylic with a White Spirit solvent, doesn't build any skin either. A lot of other protective sprays did though. All very unscientific:  I have a HP Matte Litho-Realistic Z3200 print framed without glass but sprayed with Talens in the office now for 9 months. Doesn't take dirt from the air and still looks well in color and paper white, it has no FBAs so they can not change either. That paper is cheap so I go with the idea of replacing rather than best protection.

There is a Lascaux document: 3_synthetic_resisns_varnishes.pdf that gives more specs on what is available for conservation jobs.


met vriendelijke groeten, Ernst Dinkla

New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm

 

[dgberg]

I don't think the aqueous-coatings are all that great for photo type inkjet media. The low-viscosity solvent sprays like Print Shield are most appropriate for the photo type surfaces because they create a thin conformal coating, thus leaving the initial media surface texture more intact. The aqueous-based coatings like Eco Print Shield are more appropriate for canvas because traditional decorative finishes used on canvas are generally brushed on and create a fairly thick final coat. The traditional aesthetic of a fully varnished canvas painting is more of the the look artists are going for with these types of overcoats.

Most of my own personal printing is on the papers like Canson Platine Fibre Rag, Hn Photo Rag Baryta, etc. I'm slowly coming to the conclusion that sealing the microporous ink receptor layer with a thin conformal acrylic coating like Print Shield is really important. Yup, its a PITA and by the time one gets finished spraying a large print you will have more money in that final coating than you do in the ink used to make the image. Ouch! Nevertheless, I think microporous inkjet prints really benefit from sealing those pores with a top coating.

Premier implies the protective benefit is largely due to UV blockers in the spray, but I really doubt that. Even with three or four coats applied, the final coating is too thin to filter out much UVA radiation. Normal glazing like ordinary picture frame glass filters out the UVB/UVC rays, so evaluating UVA radiation attenuation is the key this product claim. Try an experiment with Print Shield on an an OBA-rich paper like Epson Exhibition Fiber. Cover half the paper and spray. Then look at the paper under blacklight. If the coating was a  highly effective UV blocker, the coated side wouldn't glow under blacklight. But it does...almost as much as the non sprayed side. So, what's going on here? By sealing the pores, the light-induced and ozone-induced oxidation rate of the colorants is being significantly reduced because the surface area-to-volume ratio of the microporous ink receptor coating is being radically altered.  In AaI&A tests and those done by WIR, fade resistance can nearly double when Print Shield (also, re-badged as HN Protective Spray, etc) is used. And equally important, the image layer now has much better scratch and abrasion resistance, so it's a win-win for durability despite being a total PITA to use and expensive as well.

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



Mark,
In reference to the cost issue. You hit the nail on the head with regards to spray topcoating costing more then the ink. My search is still on for a more cost effective solvent based product.
The Clearjet 2000 @ $13.00 for 12 oz. can is pretty steep. I just sprayed 3 - 8/12 x 11" metal prints with a 12 oz. can which comes out to about $4.50 for a 1 square foot print. Ink cost for me is about  50 cents a sq. foot.
I have the Clearstar FA in gallons but at $100 or so it's not much better from a cost per print perspective. I am headed out this morning to buy some of the Krylon Crystal Clear product ($4.99 for 11 oz. can.)and am very anxious to give it a try at around a 60% savings. Will be using it on metal and metallic prints.

[MHMG]

Mark,
In reference to the cost issue. You hit the nail on the head with regards to spray topcoating costing more then the ink. My search is still on for a more cost effective solvent based product.
The Clearjet 2000 @ $13.00 for 12 oz. can is pretty steep. I just sprayed 3 - 8/12 x 11" metal prints with a 12 oz. can which comes out to about $4.50 for a 1 square foot print. Ink cost for me is about  50 cents a sq. foot.
I have the Clearstar FA in gallons but at $100 or so it's not much better from a cost per print perspective. I am headed out this morning to buy some of the Krylon Crystal Clear product ($4.99 for 11 oz. can.)and am very anxious to give it a try at around a 60% savings. Will be using it on metal and metallic prints.

Yeah, the coverage estimate provided by the manufacturers for these sprays in a can are absurdly optimistic. Not even close.

I plan on checking out some of the Krylon offerings as well in the near future. Tapping into a bigger "home improvement/hardware store" distribution model makes the Krylon sprays significantly lower priced.  That said, I once tried Krylon "Preserve it" and found that the solvent was so aromatic that it hung around for weeks after spraying a print.  Nasty stuff to work with, too, but higher viscosity so it didn't need so many coats as the lowerviscosity sprays.  Krylon has some newer acrylic formulations now including one they call "low odor", so probably time to revisit the subject once again.

cheers,
Mark

[Alan Goldhammer]

Yeah, the coverage estimate provided by the manufacturers for these sprays in a can are absurdly optimistic. Not even close.

I plan on checking out some of the Krylon offerings as well in the near future. Tapping into a bigger "home improvement/hardware store" distribution model makes the Krylon sprays significantly lower priced.  That said, I once tried Krylon "Preserve it" and found that the solvent was so aromatic that it hung around for weeks after spraying a print.  Nasty stuff to work with, too, but higher viscosity so it didn't need so many coats as the lowerviscosity sprays.  Krylon has some newer acrylic formulations now including one they call "low odor", so probably time to revisit the subject once again.

cheers,
Mark

I would make sure to look up the MSDS and see what the major offensive chemicals are and whether you need special type of ventilation.