Some Comments About Making Oil Prints on Hand-Coated Paper
By Andrea Zalme

I think I would tend to agree that inking hand coated paper is easier than inking a regular Bromoil. At least I was very surprised by how easily my first try inked up. I would guess that this is because the handcoated papers are not supercoated.

Interestingly enough though, I find that my limited experience with handcoating seems to indicate that a contrastier negative is easier to work with. My emulsion coating technique has changed with every print I have made and I was having a lot of trouble with my latest print (too many variables changing here?), but when I used a negative that previously gave good results, I also got good results using my new emulsion. The good negative appeared to be more open and had a higher contrast than my latest enlarged negative which was rather soft and low contrast.

I have also been adjusting my dichromate concentration (I have been using 3% and 5% solutions) and found that the 5% gave better results. Maybe it's a matter of adjusting my exposures? I think one of the problems in my work at the moment is that I have not yet been able to nail down a lot of the many
variables involved.

I have started out with a paper soak at approx. 120 F and then squeegee it onto a sheet of heavy glass that has been warmed by a hot plate which has been adjusted to approx. 100 -110 F. I find that 10ml of gelatin solution for each 35 sq. in. of paper gives good coverage. I measure it out into a small plastic dispensing cup kept warm in a water bath before I smooth the paper onto the glass. Then I pour the gelatin into the center of the paper and smooth the solution from the center out with a small comb. I have not found air bubbles to be much of an issue in my experience so far.

My gelatin formulation however is somewhat different. I have not yet tried
to use starch in my mixture although I have bought a box of potato starch to
use for just that purpose. Maybe I will try it when I next coat paper. I have not tried adding sugar to the gelatin as I have visions of little critters devouring my image and have been rather hesitant to use it. Instead I have used a small amount of glycerin in my solution. It seems to not only help with water absorption but also allows the paper to dry with less of a curl. I also add a small amount of wetting agent like Kodak Photo-Flo to the gelatin solution and this seems to help minimize the formation of bubbles.

To harden the gelatin, I use a Glyoxal bath after the paper has been coated
and dried. I generally mix up more gelatin than I need at any particular time and store it in the refrigerator. Adding a hardener to the solution when I make it would not allow me to do that. I have not worked with the process long enough to be able to judge the relative merits of either method yet but it seems to work well for me and I appear to get good water absorption and a nice relief in the gelatin after soaking the matrix.

I generally use a sensitizing solution of 5% Potassium Dichromate with an
immersion time of approx. 3 minutes for my oil paper. I have been dipping my
paper into the sensitizer as I have been concerned that brushing it on would
not allow for an even coating resulting in variable sensitivity across the paper. I have also wondered whether the gelatin would be completely sensitized or if it would just be a surface effect. When I think about it, brushing would probably be preferable if it works well, because of the lower amount of dichromate that would be washed out during clearing.

To clear the print after exposure I have been using Potassium Metabisulfite.
Simply because I already use it to clear my gum prints and I have it on
hand. It seems to work well but I have found that if I leave a print in the
solution a bit too long the more heavily exposed areas of the print begin to
take on a blue tint.

That's pretty much the process I am using at the moment but that could
change at any time. So far this method has given me the best coatings of any
technique I have tried so far and I will need to play with it for a bit just
to see how well it works for inking.

On Exposure
As of yet I have not done any rigorous exposure testing because my papers
have been so variable up to now. My method has been to tape the negative to
the paper (no split back print frame here) with '3M Paper First Aid Tape".
Just stick the tape in the margin of one side of the sheet of film so it acts as a hinge. It is relatively transparent to UV and is fairly low-tack. I will check the paper by lifting the film after my first exposure and if the dichromate has not darkened yet in the highlight areas of the print, I will expose for a longer time.

The darkening of the dichromate is quite apparent and I am able to see the entire image on the paper after exposing. The stain comes out after clearing and a fairly obvious relief can be visible. When I use my known good negative I can ink the paper quite easily.