harvesting silver from over-exposed paper

knoxissimpler · May 5, 2008

Hi, I have a large stack of photo paper that was ruined due to a classmate kicking open the single door to the darkroom... I tested the paper, and it is all ruined. Is it possible to somehow separate the silver from the paper? I saw someone once remove the silver from fixer, and I thought of using some fresh fixer and just running undeveloped paper through it to strip the emulsion. Will this work?
I also, as a side question, wondered: since the silver in the fixer is removable by redox (I've seen it with steel wool), is it possible, using an electric current, to put it back into a fresh silver chloride emulsion using a current and a saltwater solution?

edit: also, I have some homemade emulsion that went bad, I thought about reacting it with copper to get silver metal, then using an electrical redox reaction in the same way as above, with a salt solution, to make silver chloride... will this work as well?

glbeas · May 5, 2008

That will work for removing the silver. Don't know about rechlorinating the silver though. It would be easier to sell the silver and buy some fresh photo grade silver nitrate.
Also if you want to go to the trouble of washing and drying the paper it can be reused for alt processes. Ask Kerik about it.

knoxissimpler · May 5, 2008

I did not know that any alternate processes use completely exposed paper! which ones so, so you have a link? I have a lot of this paper I saved for the purpose of removing the silver that was ruined (the photo head here told me to put it to use, the second that Kodak stopped making photo paper, this guy splurged on it like crazy... he was pi**ed!

Brook · May 5, 2008

You could toss it out in the sun to really over expose it, develop it, and use it to make an ass kicking hypo-alum toner.

knoxissimpler · May 5, 2008

I just realized, the reaction with salt might make pure sodium metal, which is not good in a water solution (unless it's a lake you make things go boom on B - )
anyways, I thought about actually reintroducing the emulsion (removed from the paper) into an aqueous solution, causing them to reform when dried... or using copper hydroxide or copper carbonate in the reaction to replace the salt

or I could dissolve the silver in some nitric or sulfuric acid

Johnny was a chemist's son, but Johnny is no more,
what johnny thought was H20 was H2SO4!
so yes, I know the dangers of doing the above with the acids, before any comments.

Kirk Keyes · May 6, 2008

knoxissimpler said:
I just realized, the reaction with salt might make pure sodium metal, which is not good in a water solution (unless it's a lake you make things go boom on B - )

This will not happen - you cannot make sodium metal this way.

knoxissimpler · May 6, 2008

Quote:

Originally Posted by knoxissimpler View Post
I just realized, the reaction with salt might make pure sodium metal, which is not good in a water solution (unless it's a lake you make things go boom on B - )
This will not happen - you cannot make sodium metal this way.

Click to expand...

then where would the sodium go? it would be a single replacement reaction if it happened, would it not?

donbga · May 6, 2008

glbeas said:
That will work for removing the silver. Don't know about rechlorinating the silver though. It would be easier to sell the silver and buy some fresh photo grade silver nitrate.
Also if you want to go to the trouble of washing and drying the paper it can be reused for alt processes.

One would need an extremely large amount of paper to make silver recovery financially worth the trouble.

Fixed out B&W fiber based paper can be used for carbon transfers but the paper has to be throughly washed. Also some B&W papers (I don't know which) may not work well for carbon transfers.

I have a friend here locally who has used the back of fixed out gelatin silver paper to do palladium printing so it may work well for other iron processes. I well say that I didn't care much for the texture of the surface that showed in the prints.

gainer · May 6, 2008

When one considers that the major cost of manufacturing paper and film is not the silver, one wonders if the silver recovered is worth the cost of recovering it. At least, this one does. You could weigh several sheets of dry paper, bleach, fix and dry it and weigh it again to see how much difference the silver could have made. You might find out that the cheapest thing you can do with the ruined paper, if you are worried about the effect on the environment of just pitching it, is piitching it at a hazardous waste dump. If it is fiber-based paper, you could remove the emulsion with chlorine bleach and use the paper for other art purposes. I think the paper is worth more than the silver on it. Just a thought.

Kirk Keyes · May 6, 2008

knoxissimpler said:
then where would the sodium go? it would be a single replacement reaction if it happened, would it not?

I kind of have a hard time following what you are proposing, but I think you are saying you want to take the bad paper, remove the silver from the paper with fixer, and then you want to put the silver back into the paper using electrolysis.

It's that last step that will not happen. I assume you think that electrolysis will create silver metal, which you think will react with the sodium chloride that you've added to the fixer solution - and then the sodium will be left behind as free metal?

That's not going to happen - remember that the sodium in the sodium chloride is ionic sodium. It's in solution and it will stay in solution. If you drop out the chloride ions from the solution with the silver, you still have the ionic sodiums floating around. I thint what they will probably do is start raising the pH of the solution.

knoxissimpler · May 6, 2008

I kind of have a hard time following what you are proposing, but I think you are saying you want to take the bad paper, remove the silver from the paper with fixer, and then you want to put the silver back into the paper using electrolysis.

It's that last step that will not happen. I assume you think that electrolysis will create silver metal, which you think will react with the sodium chloride that you've added to the fixer solution - and then the sodium will be left behind as free metal?

That's not going to happen - remember that the sodium in the sodium chloride is ionic sodium. It's in solution and it will stay in solution. If you drop out the chloride ions from the solution with the silver, you still have the ionic sodiums floating around. I thint what they will probably do is start raising the pH of the solution.

you seem to have misread the thought (I can see why, I am not very good at wording things sometimes), I thought about taking the silver as a cathode and use a salt anode (the chem teacher here has one, I would use the hydrogen b/c I can then make one, but that would produce HCl acid) and using electricity, cause the single displacement reaction:
Ag(s) + NaCl(aq) --> Na+ (s) + AgCl(aq)
but that would be dangerous...

also, I do not have in mind financial benefits, but I hope to A) safely dispose of my spent fixer B) make use of the ruined paper some how, and I have been doing projects in making my own emulsions, and I thought I might find a way around using silver nitrate since it is hard to get a hold of and not something I would want to sit in my house for a long time C) learn more about electrolytic solutions of metal salts

also, I think that if the unaltered (though exposed) silver chloride were lifted from the paper, and put into an aqueous solution, the ions (having broken apart into Ag+ and Cl- [or Br- etc] would lose the effects of having been activated, at least if a current was used with a sacrificial anode (the cathode would also be silver, but after noticeable changes to the anode and cathode, the current would be reversed)

dancqu · May 6, 2008

knoxissimpler said:
then where would the sodium go? it would be a single
replacement reaction if it happened, would it not?

Should there be any instantaneous production of free
sodium it would immediately combine with water forming
sodium hydroxide and free hydrogen. Dan

gainer · May 7, 2008

Sodium hypochlorite also seems to be a possible product. Calcium hypochlorite (Chlorox) is very unfriendly to gelatine, so I would expect the sodium compound to be as well or more so.

A rehalogenating bleach such as is used in the bleach-redevelopment method of sulfide toning, would be a better way to get a rudimentary silver chloride emulsion out of thorouhly exposed and developed printing paper emulsion, I would think. If you experimented with sodium chloride and/or sodium bromide in different proportions in the bleaching solution, you might get something interesting. At least you'd have a little fun trying.

Kirk Keyes · May 7, 2008

gainer said:
Calcium hypochlorite (Chlorox)

Pat - Clorox is sodium hypochlorite.
http://www.thecloroxcompany.com/products/msds/bleach/cloroxregularbleach0505_.pdf

Kirk Keyes · May 7, 2008

gainer said:
A rehalogenating bleach ...

So following Pat's idea here, you could develop the exposed paper to convert the exposed silver halide into metallic silver, and then use a rehalogenating bleach to form fresh silver halide in situ. If it's done in the dark, I think it would be light sensitive at that point. Dry the paper and make some test exposures.

It's a lot of work, but it would be kind of fun to be able to say you've done it.

gainer · May 7, 2008

Kirk Keyes said:
Pat - Clorox is sodium hypochlorite.
http://www.thecloroxcompany.com/products/msds/bleach/cloroxregularbleach0505_.pdf

I guess I was thinking of the water purification pills we used to get with field rations. Were they not calcium hypochlorite?

Kirk Keyes · May 7, 2008

Could be - it's used for water treatment. But I never served so I can't say.

glbeas · May 7, 2008

Actually calcium hypochlorite was used as a powdered bleach. Keep it away from ammonia compounds, it will get nasty.

dancqu · May 7, 2008

Kirk Keyes said:
So following Pat's idea here, you could develop the exposed
paper to convert the exposed silver halide into metallic silver,
and then use a rehalogenating bleach to form fresh silver
halide in situ.

Skip the exposure and developer. Use a strong reducing
agent in solution to reduce the halides. Perhaps oxalic
acid would do and not leave a mess. Oxalic acid,
rings a bell. IIRC it is used for some alternate
photographic purposes. Dan

removed account4 · May 8, 2008

can you fix and wash all the paper
and use it to coat with alt process materials?

pt/pd, cyanotype or even hand coated silver gelatin ..

gainer · May 8, 2008

Actually, I think you could use Iron Out, obtainable at most supermarkets in the cleanser department. It is sometimes described as a developing agent, but it has such a high fog level that if you leave film or paper in it long enough, it will go to completion. I don't see that the development is so messy. You could also use ascorbic acid or hydroquinone in a strong carbonate solution to blacken it, then wash and dry it, and you'll have a very black emulsion. The bleaching is also only a single soak, wash and dry operation. It won't take much time or money to find if it's worth doing more of.

knoxissimpler · May 8, 2008

ok, so I run the exposed paper though a rehalogenating bleach, and that might reform the silver chloride/bromide [etc] so that it is no longer activated? will it still be on the paper, or aqueous in solution, needing to be applied to the paper.

and if the paper is already exposed, why would I need to run it through Iron Off??

pnance · May 8, 2008

Actually, most water purification tablets contain iodine as the active ingredient.

knoxissimpler · May 8, 2008

pnance said:
Actually, most water purification tablets contain iodine as the active ingredient.

How would I want to use that? what form of iodine is it? Where on the activity series is Iodine compared to silver?

gainer · May 9, 2008

knoxissimpler said:
ok, so I run the exposed paper though a rehalogenating bleach, and that might reform the silver chloride/bromide [etc] so that it is no longer activated? will it still be on the paper, or aqueous in solution, needing to be applied to the paper.

and if the paper is already exposed, why would I need to run it through Iron Off??

Exposed silver halide is not necessarilly silver. You need to reduce the exposed silver halide to silver. Iron Out is a reducing agent composed mostly of sodium thiothionite IIRC. It will blacken the silver halide by reducing it to metallic silver and a different halide compound. I'm sure there are many other chemicals that will reduce the silver halide. A developing agent is a reducing agent that responds preferentially to exposed silver halide. There are many of these as well. If you use one that is not preferential, you will not have to expose each sheet to light in order to be sure of reducing all the silver halide.

Unless you use something like chlorine bleach that takes off the emulsion, most of the silver if not all will remain in the emulsion just as the silver image remains in the emulsion after noemal fixing.

This solid black "image" is not active. The problem I see in going straight to the bleach while there are still original halides of silver remaining along with photolytic silver is that I suspect that the bleach will convert the photolytic silver to the bromide and/or chloride that you put into the bleaching solution while leaving the original silver halide, thereby causing uneven sensitivity, resulting in mottled images.

harvesting silver from over-exposed paper

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