- Joined
- Feb 22, 2011
- Messages
- 4
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- 4x5 Format
Hi,
I'm another one of those hybrid people trying to use traditional processes to solve modern problems. I am researching and testing the process of using photographic grade gelatin to coat modern pigmented inkjet prints. The problem we are trying to solve is that although pigmented inkjet prints offer great light fastness, the various inkjet coatings are porous even after printing and are susceptible to pollutants and the pigmented ink sits on the surface of the paper/coating and is susceptable to scuffing and scratching. Commercially available poly coatings change the aesthetic of the surface in a way that many of our clients do not like.
The test samples include three different paper types: 1. Fine Art Rag paper that is matte. 2. Fine Art paper with a semigloss coating and baryta layer. 3. Commercial RC base, with semigloss coating.
I have tested various dilutions (1%, 3%, and 7%) of photographic grade gelatin using two different hardeners (Glutaraldhyde and Chrome Alum). I have begun to achieve interesting results, but with complications that leads me to several questions.
The initial results are encouraging because the gelatin coating does increase the scratch and scuff resistance of the pigmented inkjet print. The maximum benefit seems to be achieved at 3% dilution and the 7% just increases the possibilities for defects. The FA matte paper retains it's matte look while getting the benefit of the scuff resistant gelatin coat. The FA baryta paper, results in a more even semi-gloss and any gloss differential or bronzing characteristic of the uncoated print disappears. The Commercial RC paper also results in a more even semi-gloss and any gloss differential or bronzing characteristic of the uncoated print disappears.
The dissolved gelatin while still at 30˚C or so, is very liquid or water like in viscosity. I found that trying to use a coating rod (No. 90 Coating Rod. Stainless Steel, and 5/8 inch diameter) is not working because of the low viscosity leaves too much solution on the print so I either roll on the coating with a HD foam roller, or just dip the print in the solution. In any case I let the excess solution sun off of the print and I hang the print for drying. But, the gelatin solution does not drip off perfectly evenly and I get some streaks, and some dried bubbles. I've tried adding a wetting agent (hyper wet) but at various dilutions I'm not seeing an improvement, and there is a residual film visible on the print surface from the hyper wet solution. So, I'll be experimenting with using isopropyl alcohol instead. Also, it seems that there are more streaks in the Dmax areas. I'm not sure if this is because of adhesion differences or other problems. Any opinions on wetting agents?
I also have questions about hardeners. I understand that one benefit of hardening is protection form fungus growth... I assume there is a retained effect in the dried print.
When I coat prints the gelatin is still warm, so it is very liquid. When the gelatin cools it firms up; some solutions more than others. I have varied firmness depending on gelatin dilution and hardener... actually, I don't know if the hardener is affecting that. Since the coating seems to dry fine on the print surface even if the remainder of the gelatin does not dry to a firm state (it will run if tipped to 45˚ angle) does this matter? Should I be trying to achieve a gelatin that will dry to firm state when left in an open container at room temperature? When carbron transfer people are talking about achieving the proper gelatin hardness, what are they looking for and does this matter with this application?
I'm leaning towards using Glutaraldhyde for hardening an drop experimenting with the chrom alum, especially do to the caustic nature. Any opinions on the best hardener or if it matters?
Lastly, I'd also like to add UV blocking to the gelatin. Does anyone have experience or knowledge about adding UV Blockers to gelatin coatings. I've considered using nano fine ZnO, but it's still a particle and does not dissolve. So I don't know if the small amount I'm able to suspend in solution adds any UV blocking. Any input?
Best,
Ken Allen
kenallenstudios.com
I'm another one of those hybrid people trying to use traditional processes to solve modern problems. I am researching and testing the process of using photographic grade gelatin to coat modern pigmented inkjet prints. The problem we are trying to solve is that although pigmented inkjet prints offer great light fastness, the various inkjet coatings are porous even after printing and are susceptible to pollutants and the pigmented ink sits on the surface of the paper/coating and is susceptable to scuffing and scratching. Commercially available poly coatings change the aesthetic of the surface in a way that many of our clients do not like.
The test samples include three different paper types: 1. Fine Art Rag paper that is matte. 2. Fine Art paper with a semigloss coating and baryta layer. 3. Commercial RC base, with semigloss coating.
I have tested various dilutions (1%, 3%, and 7%) of photographic grade gelatin using two different hardeners (Glutaraldhyde and Chrome Alum). I have begun to achieve interesting results, but with complications that leads me to several questions.
The initial results are encouraging because the gelatin coating does increase the scratch and scuff resistance of the pigmented inkjet print. The maximum benefit seems to be achieved at 3% dilution and the 7% just increases the possibilities for defects. The FA matte paper retains it's matte look while getting the benefit of the scuff resistant gelatin coat. The FA baryta paper, results in a more even semi-gloss and any gloss differential or bronzing characteristic of the uncoated print disappears. The Commercial RC paper also results in a more even semi-gloss and any gloss differential or bronzing characteristic of the uncoated print disappears.
The dissolved gelatin while still at 30˚C or so, is very liquid or water like in viscosity. I found that trying to use a coating rod (No. 90 Coating Rod. Stainless Steel, and 5/8 inch diameter) is not working because of the low viscosity leaves too much solution on the print so I either roll on the coating with a HD foam roller, or just dip the print in the solution. In any case I let the excess solution sun off of the print and I hang the print for drying. But, the gelatin solution does not drip off perfectly evenly and I get some streaks, and some dried bubbles. I've tried adding a wetting agent (hyper wet) but at various dilutions I'm not seeing an improvement, and there is a residual film visible on the print surface from the hyper wet solution. So, I'll be experimenting with using isopropyl alcohol instead. Also, it seems that there are more streaks in the Dmax areas. I'm not sure if this is because of adhesion differences or other problems. Any opinions on wetting agents?
I also have questions about hardeners. I understand that one benefit of hardening is protection form fungus growth... I assume there is a retained effect in the dried print.
When I coat prints the gelatin is still warm, so it is very liquid. When the gelatin cools it firms up; some solutions more than others. I have varied firmness depending on gelatin dilution and hardener... actually, I don't know if the hardener is affecting that. Since the coating seems to dry fine on the print surface even if the remainder of the gelatin does not dry to a firm state (it will run if tipped to 45˚ angle) does this matter? Should I be trying to achieve a gelatin that will dry to firm state when left in an open container at room temperature? When carbron transfer people are talking about achieving the proper gelatin hardness, what are they looking for and does this matter with this application?
I'm leaning towards using Glutaraldhyde for hardening an drop experimenting with the chrom alum, especially do to the caustic nature. Any opinions on the best hardener or if it matters?
Lastly, I'd also like to add UV blocking to the gelatin. Does anyone have experience or knowledge about adding UV Blockers to gelatin coatings. I've considered using nano fine ZnO, but it's still a particle and does not dissolve. So I don't know if the small amount I'm able to suspend in solution adds any UV blocking. Any input?
Best,
Ken Allen
kenallenstudios.com
