How to make silver nitrate working solution for salt paper printing?

Hi,

If I want to make a working solution of 100ml sensitizer for salt paper printing, how much silver nitrate would be required?

I can get it online as crystals but since it is reasonably expensive, I don't want to buy too much. I also don't like the idea of 'stocking up' on chemicals that are not needed immediately.

Also, when mixing it with distilled water, is it as easy as 1 gram silver nitrate resembles 1% silver nitrate in the solution? In other words, if I want a solution of say 14%, this would require 14 grams of silver nitrate?

The proper mix for salt printing is 12%. Weigh out 12 grams of silver nitrate dissolve in about 90 ml of distilled or RO water. When dissolved, add water to make 100 ml.

Jim Noel said:

The proper mix for salt printing is 12%. Weigh out 12 grams of silver nitrate dissolve in about 90 ml of distilled or RO water. When dissolved, add water to make 100 ml.

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What do you mean by proper mix? Do you mean your preferred mix?

As others said: a 12% solution is 100ml of solution containing 12g of silver nitrate.

I'm not sure where I originally read about this but it works very well. I have 2 small brown eyedropper bottles. They are smaller than 100ml, maybe about 30ml. The first one contains 24% silver nitrate solution. The second contains 12% citric acid solution. These solutions are supposed to keep longer by keeping them separate. The glass eyedroppers are quite consistent at 22 drops per ml.

To make a coating of 12% silver nitrate and 6% citric acid, put an equal number of drops of each into a small container. I use recyclable plastic condiment cups that are the same width as my hake brush. To make a sensitizing solution with a lower amount of CA, just replace some of the CA drops with distilled water drops. This is a flexible system and so far the solutions have kept very well.

Depending on the kind of paper and the size of the print, I use somewhere between 10 and 22 drops of each solution. My prints are between 5x7 and 7x11 inches. It's a good idea to keep notes and it does not take long to find the right amount for different kinds of paper. I've also found that with practice I need less solution to completely cover the image area.

Even though I used distilled water to make up the solutions, I've noticed a small amount of tiny black specs in the silver solution. It still works fine and I'm almost out, so I'm glad the rest of my silver nitrate is still in dry form and that I will make a fresh batch before any problems arise. Possibly if I'd made 100ml it would have needed some kaolin clay or "sunning" to keep using it. So there may be a good reason to make smaller batches.

Some people here at APUG ( from this thread even! ) have far more experience than I do and have suggested that problems will come from hake brushes eventually, and that using a glass coating rod is better. I have not tried the coating rod so I can't say anything about that, but I don't doubt their experience. What I do know is that over time I've learned to use the brush better and now my prints usually have an even coat without streaks.

Have fun!

Thanks all, this helps. I'm familiar with classic darkroom printing, but new to alternative processes.

cliveh said:

What do you mean by proper mix? Do you mean your preferred mix?

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Call it preferred, or proper, or whatever you wish. Through the years, as well as some fairly recent exhaustive tests, 12% has proven to be the best percentage solution to use for making salted paper prints. Where most people mess up is the percentage solution of the salt solution. Too many workers us too high a concentration of the Cl ion.

I have only been making salted paper prints since the 1960's. If you are using good hake brushes which don't shed you should be OK. I prefer a good sable brush which I have had for probably 40 years. A glass rod works very well and uses less sensitizer than most brushes,but it is best on very smooth hot pressed papers and when coating on a piece of plate glass.

Your specs are most likely impurities in the silver nitrate. I usually mix 200-500 ml of silver nitrate at a time.I have never added kaolin to the mix, and have had no problems with the solutions. There are probably some bottles of varying %ages sitting on my shelf which are 10+ years old.

Jim Noel said:

Call it preferred, or proper, or whatever you wish. Through the years, as well as some fairly recent exhaustive tests, 12% has proven to be the best percentage solution to use for making salted paper prints. Where most people mess up is the percentage solution of the salt solution. Too many workers us too high a concentration of the Cl ion.

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Well I beg to differ, if you read Talbot's notebooks P and Q and follow his experiments with practical tests, you will find some very interesting results using lower concentrations of AgNo3 with variations of NaCl.

Contrast control by varying the proportions of salt and/or Silver is mentioned in a couple of the "textbooks", (e.g. Farber) although without specific "worked examples".