Alt-Process Prints from Digital Negatives or Positives

[ndg]

Thanks guys! I size to prevent the image to sink into the fibers of the paper. It seems to pop more on sized paper.

[pdh]

Sizing is difficult for metal like sensitizers. Stevens mention in his book Sizing only if the paper is to open. His formula is :
7g gelatin
500 ml distilled water
1g alum
25 ml alcohol absolute

Mix and heat als normal.

I tried it and it works.

Greetings Ron

That's a very heavy size!
Is that chrome alum or potassium alum?

[ron]

That's a very heavy size!
Is that chrome alum or potassium alum?

Sorry for my late response.

7gr on 500 ml is a thin solution normal they say for normal sizing twice the amount gelatin.

And yes chrome alum.

I have tried it with unmixed and light sized kallitype. The sized one seemed a slight more dmax and a slight darker to black color. With de receipt from sevens book.

100 MG sodium acetate (the cheap food grade)
3gr tartaric acid
2ml 2% dichromate (pot / amm)
1 liter (distilled) water. (I use normal water) in Holland the water quality is very good and pure.

[ndg]

"Just the Skin" - a platinum-palladium print

Print on Berger COT-320 paper, 16" x 20"
Dig neg on pictorico

[bob carnie]

What kind of sizing proceedure are you using, do you wish to share. We seem to be having a few issues .

Thanks guys! I size to prevent the image to sink into the fibers of the paper. It seems to pop more on sized paper.

[ndg]

Hi Bob, I did not size the last image I posted. I have given up trying to use sized paper for Pd/Pt. When I did, i used gelatin and did not use any platinum in those prints as platinum supposedly binds to the gelatin. Occassionally, I have also sized with gum.

[ndg]

"The Old Church Bell" - a Palladium Print

For this, I sized the paper with gum before coating with with FeOx-Palladium.
The paper is Arches Platine.
The dig neg is on Pictorico.

[pdh]

, I sized the paper with gum before coating .

That's interesting. I have wondered in the past about whether gum sizing would work for alt-processes, but this is the first time I have found anyone referring to it directly.

As before, may I ask for a little more detail?

[Andrew O'Neill]

When you say you sized with gum, do you mean gum arabic?

[ndg]

I mix gum arabic powder and water at a ratio of 1:2. So 100 gm of gum in 200 cc of water. I leave the mixture in the fridge a few days to totally mix and dissolve. I don't add any preservatives and haven't needed to.
To size, I mix the gum with ammonium dichromate at a ratio of 2 of gum to one of dichromate.
I coat using a foam brush and dry in the dark room. Once dry, I zap it in my UV printer. I expose for the average time I need for gum prints. In my case, about 7 min. Then I clear the paper in water, solutions of sodium metabisulfite and water again.
Most times, one coat of size has sufficed. Occasionally, I've had to do a second coat.