Salted gelatin printing

Mainecoonmaniac · May 6, 2013

Today was my first time I did salt printing with gelatin. I'm getting a weird stain. It doesn't show up until I fix then wash the print. The stain intensifies in the wash. The pattern is usually on the left side where put the puddle of silver nitrate before brushing on the solution. Can a puddle of solution sitting too long before coating the paper than the rest of the print can cause staining?

Herzeleid · May 6, 2013

Yes, I know what you mean. The part you pour SN has a stronger density than the rest, probably in the same shape of the puddle formed initially. If you let it sit for long it will have different density than the rest. Pouring SN and quickly brushing might help. I don't seem to have that problem anymore.

Have you tried mixing your SN with %10 citric acid before coating (not mixed in bottle) 1+1 or 2+1, you would have more solution to coat but it seems to be working fine for me. Acid additive prevents premature fogging of paper in humid conditions, it might lessen the stain you get too.

As I said I don't seem to get that stains anymore unless I am slow to start brushing or pushing the solution. I always mix SN with some acid.

Mainecoonmaniac · May 6, 2013

Hi Herzeleid.

I never thought of that. I think you're right. You're right. I salted the paper with a solution of citric acid, gelatin and salt. I guess it isn't enough citric acid. I work by pouring out about 5mls then use a syringe to measure out what I need. I guess I can mix some citric acid into the the batch I'm using. Or possible work faster. Thanks for the suggestion.

Herzeleid · May 6, 2013

Hi,

I mix acid before coating. I did not added to the gelatin before. I do not know how it behaves, but that sounds quite reasonable. (albumen binder contains acid too)

I think 1 part %5 citric acid 1 part silver nitrate mixed before coating would work fine. I prefer %10 citric acid, but I fear 1+1 is unnecessarily diluted, so I have decided to mix %20 citric acid and add half the amount (2 + 1 ). I might even increase it to %40 to lower the dilution of SN. I am doing some testing with salts at the moment myself.

Mainecoonmaniac · May 6, 2013

I'm using a 12% solution of SN with out the 5% citric acid solution. So what concentration of SN are you using? Is it very humid where you live?

Don

smieglitz · May 6, 2013

What color is the stain? I've experienced defects in salted prints because the paper hadn't fully dried in one spot compared to an adjacent area. One part would be blue-gray and the other part maroon-gray. I started drying the paper longer before printing on it and that problem went away.

Herzeleid · May 6, 2013

Mainecoonmaniac said:
I'm using a 12% solution of SN with out the 5% citric acid solution. So what concentration of SN are you using? Is it very humid where you live?

Don

I used to use acetic acid for mixing it but now I am using citric acid. The formulas I have found on the internet often pointed to a %5 solution of citric acid, but I started using %10 because CA is a weak acid.

I am using %12 SN solution too. To coat an area of 8x10 inches I would measure 1,5ml of SN and add 1,5 ml of %5 citric acid and mix it (3ml in total that is a too much to coat IMO).

But I am rather going to do it like this for 8x10 inch, 1,5ml of SN plus mixed with 0,5ml %20 citric acid. The final solution would be less diluted with water and easier to coat IMO. Acidity would be the quite similar, slightly stronger.

It is quite arid here actually, it is around %25-30RH during the day. I use a USM humidifier in the work place and keep the humidity between %50 to %60. That is also one of the reasons I prefer stronger acidity in the mixture to ensure that the papers are not fogged prematurely. I am yet to test if low humidity or somewhat moderate humidity is better for salt print. (in terms of dmax and tonality)

Mainecoonmaniac · May 6, 2013

It's brownish

smieglitz said:
What color is the stain? I've experienced defects in salted prints because the paper hadn't fully dried in one spot compared to an adjacent area. One part would be blue-gray and the other part maroon-gray. I started drying the paper longer before printing on it and that problem went away.

The stain is brownish and usually in the left side. It's in the same shape as the puddle. It intensifies when I wash the print.

Mainecoonmaniac · May 6, 2013

Thanks!

Herzeleid said:
I used to use acetic acid for mixing it but now I am using citric acid. The formulas I have found on the internet often pointed to a %5 solution of citric acid, but I started using %10 because CA is a weak acid.

I am using %12 SN solution too. To coat an area of 8x10 inches I would measure 1,5ml of SN and add 1,5 ml of %5 citric acid and mix it (3ml in total that is a too much to coat IMO).

But I am rather going to do it like this for 8x10 inch, 1,5ml of SN plus mixed with 0,5ml %20 citric acid. The final solution would be less diluted with water and easier to coat IMO. Acidity would be the quite similar, slightly stronger.

Hey thanks for the tip! I'm going to give it a try. I'm still new to salt printing and still have to get my process perfected.
Best,
Don

cliveh · May 6, 2013

Mainecoonmaniac said:
The stain is brownish and usually in the left side. It's in the same shape as the puddle. It intensifies when I wash the print.

May I suggest that you don't put a puddle of Silver Nitrate solution on the paper and if coating by brush redip the brush in the solution as you coat.

Mainecoonmaniac · May 6, 2013

I'll give that a try

cliveh said:
May I suggest that you don't put a puddle of Silver Nitrate solution on the paper and if coating by brush redip the brush in the solution as you coat.

Still working on my salt printing technique. I'll give that a try. I'm afraid of contaminating the silver nitrate solution with from salt on the paper though.

cliveh · May 6, 2013

Mainecoonmaniac said:
Still working on my salt printing technique. I'll give that a try. I'm afraid of contaminating the silver nitrate solution with from salt on the paper though.

Then can I suggest you decant into a small pot the approximate volume you need for your given size of paper first. After repeated use, you will soon get a feel for the right amount.

Mainecoonmaniac · May 6, 2013

Thanks for the advice. I'm still figuring out how much for each 5x7. So far, 1 ml might be too much for my watercolor paper.

Herzeleid · May 6, 2013

I agree with Clive's suggestions.

cliveh said:
May I suggest that you don't put a puddle of Silver Nitrate solution on the paper and if coating by brush redip the brush in the solution as you coat.

I have just printed two test strips to see if the stains would be formed. On purposely, I poured and started coating from the middle. I must say, although they are quite weak (probably due to acidity), they are visible. and that is not good

If you pour SN to the edge of your coating area and later mask that part, it might also work.
But the simplest way seems to be dipping the brush into SN as clive suggested. I would do some tests tomorrow.

Mainecoonmaniac · May 6, 2013

Thanks Cliveh and Herzeleid. Very helpful information. Isn't APUG great?

Herzeleid · May 6, 2013

Yep it is

Herzeleid · May 7, 2013

An update...

I have increased the concentration and decreased the amount of of citric acid in order to lessen the dilution of final volume of SN+CA used for coating.
I have mixed %50 citric acid. (you can dissolve up to 70grams of CA per 100ml)

I added 1 drop of %50 CA per 0,5ml of SN.

So roughly to coat 8x10 inches area it is 1,5ml SN + 3drops of %50 CA. (The optimum amount of SN might change with paper so consider it as a guide only)

I left the coated paper in 27C %60RH condition for an hour. There was no fogging. If fogging happens it happens before the paper gets dry, so I believe the amount of CA is safe.
Maintaining the solution used for coating around the optimum volume would help IMO.The coating would be easier and less prone to problems because it would require less brush strokes or less passes with glass rod.

Regards,
Serdar

Mainecoonmaniac · May 7, 2013

Hey thanks for all your wonderful research! I'm slowly trying the glass rod. My paper is too wavy. But I'll start mixing the 50% citric acid solution.

Best,
Don

Herzeleid · May 7, 2013

My pleasure, coating wavy paper with rod is problematic. I used to do coat with glass rod. I taped the paper from all corners, sometimes the whole edge to get it as flat as possible. I am now trying DaVinci brushes, but I will try the rod again to compare.

Anyway, If anyone has a tip to flatten the wavy paper after gelatin coating, that would be great.

Loris Medici · May 7, 2013

Serdar, flattening with a dry mount press and/or (more likely to work) coating both sides with gelatin may help?

Regards,
Loris.

Herzeleid · May 7, 2013

Thanks Loris, I shall try coating both sides, since I don't have the dry mount press

Salted gelatin printing

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