What is that?

[henrit]

Folks,
Can anyone explain what is going on here?
This would be a salt print (ammonium chloride 2% plus sodium citrate 2%; sensitizer: silver nitrate 24% plus citric acid 12%, 1:1, double coated). Paper is Canson “C” à grain 200.
I had just made one good print with exactly the same working methods; the next 3 I’ve tried came out equally disastrous.
Picture 1, after exposure; picture 2, after development; picture 3, after fixing)

 

[henrit]

Sorry about print rotation.

 

[Peter Schrager]

I don't lots of salt but I'm pretty sure the silver is supposed to be 12%

 

[Bronson Dugnutt]

Salt printing is extremely sensitive to the coating process. The most foolproof method I've found is to do the initial 'coating' with the salt (and potentially gelatin) solution by immersing the entire sheet of paper in a tray with the solution rather than using a brush or coating rod. After thorough drying (overnight at least) apply the silver nitrate solution with a coating rod with as little pressure and as few passes as possible. AgCl is immediately precipitated once the AgNO3 comes in contact with the salted paper and is easily disturbed by the mechanical action of the rod/brush and will cause coating marks in the final print.

Most of the prints I've attempted by applying the salt solution via rod or brush have led to the defects you've shown here.

Edit: Regarding the concentration of the silver solution; it isn't super critical in salt printing as long as there is excess silver nitrate present on the paper after reacting with the salt sizing. I'm sure it has some effect on Dmax, but I don't believe it would cause the issues you've experienced.

 

[koraks]

Try 1.6% NaCl, 2% citrate, and then 11% silver nitrate. 0.7mm of each coats roughly a 5x7" area with a coating rod.

 

[nmp]

Does that look like solarization...tone reversal caused by overexposure?

 

[removed account4]

sorry for your troubles !
i am a newbie but i was just making some salt prints last week ...
how many coats of silver nitrate did you do ? it looks like you might have used too little.
but as i said im a newbie, so take my comment with a very large grain of salt...

have you tried sub coating the paper with gelatin ( with salt ) then putting a coat of salt water after the gel layer dried ...
and carfully brushed silver nitrate on the paper ( and use the citrate as a pre-water/wash bath ) ...
finicky process ! ( but fun )

 

[koraks]

In my experience, double coating nor sizing/precoating are required as long as the paper is suitable for the process.

 

[henrit]

Thank you folks for all kind replies.
Sorry I didn't make it clear enough: my sensitizer solution is 12% silver nitrate plus 6% citric acid , and it is made by mixing 24% silver nitrate with 12% citric acid in a 1:1 ratio. This solution doesn't keep well, and I mix just the quantity I expect to use.
Now I realize that the acid might be the culprit, by reacting somehow with the paper alcaline buffer. I'll try silver nitrate alone for the sensitizer, and my guess is this problem won't happen again.

 

[koraks]

Citric acid does help keep fog in check, so you may want to add a few drops of your 6% solution to the silver nitrate. I use 2-3 drops of 10% citric acid per ml of silver nitrate.

 

[henrit]

Thank you, koracs, I’ll follow your advice.

 

[henrit]

It seems that a sensitizer containing 6% citric acid may be too much for this paper. I've reduced the acid strength to 1 drop (12% citric acid) per 1 ml of 12% silver nitrate, and that horrible peeling pattern is gone.
My workflow:
1. a 4% gelatin layer, already mixed with the salt (2% ammonium chloride plus 2% sodium citrate) is applied by brush on the paper side that will be printed on;
2. with the gelatin layer fully dry, sensitizer is applied (a drop of 12% citric acid per ml of 12% silver nitrate);
3. when this is dry, a second layer of sensitizer is applied;
4. with the second layer fully dry, exposure is made under indirect sunlight (open shadow) or UV lamp;
5. development is made in slightly acidified water, 6 to 8 changes of tray content;
6. Gold toning (acetate or borax formula);
7. fixing (5% hypo, 2 bathes, 2 minutes each);

8. hypo clearing (5 minutes);
9. final wash (20 minutes).
The picture shown here was accidentally given a heavy overexposure (about 30 minutes, instead of the intended 12 minutes), and probably for that reason the highlights didn't clear very well. The white spots on the left hand margin are due to careless brushing.

 

[koraks]

That seems to come along nicely!
I never had much luck with salted gelatin as the first coat, unless the gelatin was reduced to something like 1%. You seem to fare better.
What kind of negatives do you use? Maybe the highlights are dark because the negative doesn't have the necessary long curve. Salt prints require pretty extreme negatives.