"recycling" old fogged film-an experiment

[AgX]

-) a red-only sensitized film will not turn into green sensitized (orthochromatic) after bleaching

-) wether any spectral sensitization will survive the treatment anyway depends on the sensitization

 

[Herzeleid]

I tested a roll film using copper bleach in order to find if the silver halide in the emulsion is turned into silver chloride entirely.

I used an expired b&w Orwo film for testing.

+I fogged the film (it was rolled on to a reel for years).
+I developed it in Rodinal 1+50 for 1 hour (May be I should have used another developer)
+I prepared 150gr of Copper Chloride in 1lt of water
+Bleached the film for 20 mins.

Rinsed it, dried it inside the dev tank.

The film definitely has some silver chloride in the emulsion, I have tested using a UV box and printed some 21 step wedge for 15mins.
The image is visible but it goes quite light (looks underexposed) after fixing. I tried rapid fixer and %5 sodium thiosulfate (added sodium carbonate) the results are the same.
The image gets lighter in the fixer but it is still there. May be longer exposure might help. Or increasing the chloride ratio might help.

The film is still developed in the rodinal so I assume the film has both AgCl and AgBr in the emulsion. So silver halide in the film is not entirely turned to silver chloride.

It is certain that the film has increased sensitivity to UV spectrum after copper bleach, so it is wiser to use UV filter to avoid haze and loss of contrast.

May be I shall try this with another developer, or try increasing the amount of copper chloride to entirely convert silver halide to silver chloride.

 

[yulia_s_rey]

Herzeleid: I think your bleach is doing it job. Printing-out might be tough due to the nature of film versus printing out paper [silver content], although I could be wrong. the method I use with a lot of success with (35mm Valca 3ASA Ortho film) is using a high strength developer like dektol or HC110 +soda until black|rinse|bleach 10-15 min|rinse +3 min|dry. Then instead of printing it out I use it in camera and then develop 2-3.5 min in same developer|rinse-stop|then fix as usual. Exposure time is about 1.5 min f/16 sunny day w/ a fast lens its under 10 seconds. As far as the UV filter goes I have to run some more tests. Although, I made a simple contact slide by placing a neg over the film and then contact printing it for two minutes w/ 40w tungsten at 30 centimeters away worked like a charm.

 

[Herzeleid]

Herzeleid: I think your bleach is doing it job. Printing-out might be tough due to the nature of film versus printing out paper [silver content], although I could be wrong.

You might be right I haven't tested unbleached film for printing out or how much it does print out in comparison to CuCl2 bleached film. A comparison would give good idea of the silver chloride content. I also might have to acidify the bleach formula. I have found copper sulfate mixed sodium chloride and added acids in some of the formula.

the method I use with a lot of success with (35mm Valca 3ASA Ortho film) is using a high strength developer like dektol or HC110 +soda until black|rinse|bleach 10-15 min|rinse +3 min|dry. Then instead of printing it out I use it in camera and then develop 2-3.5 min in same developer|rinse-stop|then fix as usual. Exposure time is about 1.5 min f/16 sunny day w/ a fast lens its under 10 seconds. As far as the UV filter goes I have to run some more tests. Although, I made a simple contact slide by placing a neg over the film and then contact printing it for two minutes w/ 40w tungsten at 30 centimeters away worked like a charm.

I will try it as regular film in camera sometime too. I am more interested in this bleached films special look rather than using fogged old films. But I have stash of orwo films it might be good to know this method anyway.

 

[Shalom]

I'd been wondering about this.

I have a couple boxes of old 4x5 and 3a sized glass plates. I mean so old that the concept of the expiration date hadn't been invented yet, so I have no idea how old they are, except that they're likely pre-war, and you can pick which war. I tried exposing one by strips and found the whole thing was fogged black, so they've been sitting on the shelf waiting for me to figure out what else I could do with them. I'd been wondering if there was some way to "de-expose" them such that I could use them in a camera; everyone I asked assured me it couldn't be done, but this looks like it might work.

Sure they'll be slow, but they weren't all that fast to begin with...

Any suggestions specifically for these?

edit: only developer I have in the house is HC-110 at the moment (not counting the various ingredients of caffenol-C). Would HC-110 work for this purpose? I would have to go to B&H to pick up the bleach in any case, should I get some other developer?

edit: would this be safe under a ruby safelight? The plates were orthochromatic to begin with, and would presumably now be monochromatic, but it couldn't hurt to check. I'm gonna be stuck in the darkroom until they dry anyhow, I'd rather not be in total darkness.

 

[hacked - sepiareverb]

am I the only one who is confused as to how the fully developed silver from step one is removed by fixing later?

edit: Oh, duh. all the developed silver becomes re-sensitized and so then soluble in fixer if not developed out.

 

[Herzeleid]

copper chloride bleaches the fully developed silver and then re-halogenates it. Re-halogening is the key, for example potassium ferricyanide bleach does not re-halogenate the silver. Correct me if I am wrong.

 

[newcan1]

If Ferricyanide bleach doesn't rehalogenate, why does it contain potassium bromide?

I was rather hoping it does rehalogenate.

 

[Herzeleid]

Sorry, for the confusion I was referring to a single pot. fer. cyanide solution, not its combination with potassium bromide.

 

[Fanshaw]

why fog the film?

I remember reviving some old bromide paper by soaking it in potassium permanganate solution and then washing it. The idea was to oxidise any silver metal particle, hence reverse the effect of exposure to light or other radiation which occurs after prolonged storage.Only a tiny proportion of the emulsion would have been converted to metallic silver so once the silver had been removed the remaining emulsion would work normally.I had some success with this.

 

[pdeeh]

Fanshaw that is rather interesting. Without wishing to take the thread too far off topic, could you give a few more details? Was it simply a solution of permanganate in water? if so, what weight/volume?

 

[newcan1]

This is interesting, kind of a variation of what I raised in post #18, except I contemplated developing the unexposed,fogged film first. But doesn't developer just act as an amplifier? Perhaps Fanshaw is suggesting something like just bleaching the unexposed, undeveloped film to treat the miniscule amount of latent silver, unamplified by development?

Would the permanganate have been used with sulfuric acid or sodium bisulfate, as used some times with reversal bleaches?

And what about using a rehalogenating bleach instead?

I may try this with my old FP3.

 

[Fanshaw]

Unfortunately I can't remember the permanganate concentration. I am sure however that it was just permanganate solution without additives.

 

[yulia_s_rey]

hmm...rather confused on this one

I recycled another spool of 35mm Valca 6 Din using the same process as in my first post, only this time I used Dektol 1:3 instead. After determining in the darkroom that my film speed is around .0015 ASA I wanted to put my calculations to practice, and after taking a few bracket shots I decided why not try some taking some with color filters. Now, when I developed the film I was surprised to see that my photo taken with the red 25 filter came out at all, I mean in the end, isn't re-hal film just blue sensitive? I know about the phenomena that happened with the first tricolor photograph (Maxwell) but as you can see in the red filter positive both the red tail-lights and a red sticker on the trunk came out, plus look at the golden leaves on the tree to the left of the garage.
UV filter f1.7/8s Green (58) filter f1.7/16s Red (25) f1.7/64s
So just out of curiosity, I combined the three negatives in Photoshop (I know I cheated digitally, but I didn't tweek any levels or anything, I just combined the positives in rgb color layers and then aligned them) and I got a color image! In theory, this shouldn't be happening right? Any insights?

 

[yulia_s_rey]

correction: I should've measured for .005-.006 ASA hence why they're a stop over

 

[Rudeofus]

Your film is so spectacularly insensitive, that the UV attenuation from your red filter doesn't change much. If you can get the process sufficiently reproducible, you should see a slight difference in film sensitivity with and without red filter.

BTW: you may be able to get better results if you add KBr to your CuCl2 bleach. We all know from Microdol that Chloride is a weak Silver solvent, whereas if you add Bromide this effect should be mostly suppressed.

 

[yulia_s_rey]

I see. Is there a particular name for this effect? (I'm quite cat-like when it comes to curiosity)

 

[Gerald C Koch]

copper chloride bleaches the fully developed silver and then re-halogenates it. Re-halogening is the key, for example potassium ferricyanide bleach does not re-halogenate the silver. Correct me if I am wrong.

While the bleach may convert the silver to silver chloride, modern films are mostly silver bromide with some silver iodide. In addition all the sensitizing dyes are washed out. This thread does not describe something wondrous but rather a pointless experiment. Sorry.

 

[Photo Engineer]

If you want more speed, use a Ferricyanide / bromide rehal bleach. There are many formulas here and there on APUG and the internet. Use the same exact process, but use the ferri rehal bleach instead of Copper Chloride. This change will give you AgBr which is sensitive to visible light and will give more speed.

If you wish, after you finish the entire rehal process, you can bathe the film in a 10% solution of Erythrosine and then wash until the water changes from red to clear. Now, if you are lucky, you have an orthchromatic film to use and it will have either less or more speed. It will be less if too much dye is used and more if you used just the right amount.

PE

 

[Rudeofus]

I see. Is there a particular name for this effect? (I'm quite cat-like when it comes to curiosity)

The effect is simple: while Silver Chloride (AgCl) is quite insoluble, Silver also forms higher order complexes with the Chloride ion which are quite soluble. That's the reason why NaCl in Microdol-X increases its solvent property, and why a saturated NaCl solution can even work as make shift fixer for Silver Chloride paper. You read correctly, NaCl won't fix AgBr or AgI, because AgBr is by orders of magnitude less soluble, so you can't fix film that way, at least not to archival standards.

Conclusion: CuCl2 might work well if diluted, but once you make it more concentrated, it will eat away some of the Silver Chloride just formed. By adding KBr you form mostly AgBr, not AgCl, and that won't be dissolved in quantity by Chloride.

 

[yulia_s_rey]

Thanks Rudeofus and PE, I will try the ferricyanide/bromide bleach.

 

[Gerald C Koch]

It has been my experience that copper bleaches cause softening of the emulsion.

 

[yulia_s_rey]

It has been my experience that copper bleaches cause softening of the emulsion.

I agree, they do very much so. Not an ideal bleach at all. I recall the mordançage technique uses copper chloride, while it bleaches allowing for re-exposure, it also does one heck of a job on the emulsion.

 

[Photo Engineer]

That is why, when re-exposure is desired, we use a Ferricyanide / Bromide bleach.

PE