Exposing silver halide to light, reversable reaction?

I am posting this question out of curiosity. I was reading on sepia toning, and use of a ferricyanide bleach to convert silver to silver halide. this as you all know is also done in other processes such as c41, e6 and RA4; (a few atoms of silver form when exposed making the halide crystal developable). Now what if you expose, then decide you want to re-use the film/paper/emulsion without developing it, so you bleach it with ferricyanide or other bleach, (converting the few silver atoms back to silver halide), wash it with distilled water and let it dry (all in the dark or under appropriate safe lighting if the film is ortho)
If this works how i think it does, then surely you can "re use" any silver halide product if you say shoot it, then find you want to shoot something better.... I would love to try it but lack any bleach (anything other than ferricyanide?) as i dont have my RA-4 chemicals yet and am out of C-41)... would be an intresting thing to try....

I'm not so sure that this would work, but i really don't know. I'm interested to hear what you find out. try it!

The practical answer to your question is no because various chemicals like sensitizers are removed from the emulsion. What is left is silver halide which is sensitive to light but will not react in the same way as the original film or paper.

This can be done, but it causes the film to lose all of its original sensitivity due to the destruction or disruption of the grains and the original chemical and spectral sensitization placed on the grains by the manufacturer. The film emulsion reverts to a simple blue sensitive emulsion with low speed, usually in the ISO 3 - 40 range if you are lucky. If it is high enough in iodide, you may actually fog the emulsion totally.

This subject comes up from time to time. It is a common minconception.

Also, no rehal bleach should be attempted with a color film or paper bleach. The ammonia content is enough to dissolve a fair portion of the finer grains rendering the film or paper useless. Any rehal process must be conducted in an environment free of any silver halide solvent.

PE

This question reminds me of the magical pill said to have been discovered in the middles ages that would cure any disease. Not only that but the pill could be used over and over. How the pill was to be recovered was sort of glossed over.

Gerald C Koch said:

This question reminds me of the magical pill said to have been discovered in the middles ages that would cure any disease. Not only that but the pill could be used over and over. How the pill was to be recovered was sort of glossed over.

Click to expand...

The modern equivalent of that tale of course being the nuclear industry promising to cure our climate problems and solve our infinite demand for energy, without ever answering the question what to do with all the waste they generate, nor answering direct safety issues, the likes of which we saw in Russia and Japan...

And to be honest, in terms of nuclear energy, I am pretty sure human failure (or should I say megalomania?) is probably the worst of the two major causes we can count on to haunt us again in an unavoidable future disaster...

But to get back on topic, get the nice small book by Rober L. Shanebrook that Photo Engineer was so kind to announce in this thread:

How does Kodak make film:
(there was a url link here which no longer exists)

After you've read just the first few pages, or skimmed it's pages, it should be without doubt what high tech product modern film is, and that your question is answered by a resounding no...

And, the only practical way to save analog is to create a broad base of you people who know how to make their own film and paper in their own darkroom. You APUG members are the only ones Bob and I can rely on that we can teach. But, it seems that very few are willing to learn. So, Marco, what to do about it? I'm stuck.

PE

Photo Engineer said:

And, the only practical way to save analog is to create a broad base of you people who know how to make their own film and paper in their own darkroom. You APUG members are the only ones Bob and I can rely on that we can teach. But, it seems that very few are willing to learn. So, Marco, what to do about it? I'm stuck.

PE

Click to expand...

Maybe its about time we get used to the look of single coated natural non-sensitized blue sensitive emulsions again... and scratches, and dust and all other things that haunted 19th century photographers

Although Robert's book has fully opened my eyes to what high tech and extremely well thought out productions plants Kodak and other major film manufacturers have put down in the past to overcome all of these problems, and to deliver us the highest quality and most reliable and cosistent films ever in the history of photography, reading the booklet also made me fully aware that such advanced factories will never be cost effective unless a significant bulk demand for film remains.

The length to which Kodak, and probably other companies like Fuji and Ilford, have gone to create a highly consistent and reliable production process, is astounding as seen from Robert's book...

Marco B said:

Maybe its about time we get used to the look of single coated natural non-sensitized blue sensitive emulsions again... and scratches, and dust and all other things that haunted 19th century photographers

Click to expand...

I don't think we need to accept that. I am trying to make plans to go to PE's next class. And I think others will too.

Do I think there will be throngs of people making cottage film in 20 years? No. But I think the art will live.

I think one issue about class attendance is getting the word out. I wonder if the slick magazines like Pop Photo would offer a public service announcement.

Another issue I perceive is that what Ron and Bob probably should be doing is "Train the Trainer" classes rather than end use classes. Not that I think there's any market for that yet either, but for people to keep it alive in their home darkrooms there probably needs to be at minimum a handful of art schools teaching the techniques.

I remember years ago my roommate was an art major, and I was surprised at what an excellent metallurgical education he got in the art department. Far better than the Materials Science guys got. When he started grousing around about making sculptures the department head helped him make several bronze castings. I'm here to tell you that a 4 foot high bronze statue might fit in the trunk of your car, but it will overload it for sure.

That's the kind of programs we need.

michaelbsc said:

Another issue I perceive is that what Ron and Bob probably should be doing is "Train the Trainer" classes rather than end use classes. Not that I think there's any market for that yet either, but for people to keep it alive in their home darkrooms there probably needs to be at minimum a handful of art schools teaching the techniques.

Click to expand...

I don't think so. Many, and maybe I should say most, people, even if they don't know it yet, have it in them to become some form of trainer or teacher.

Don't we all learn how to cook from our mums?

Sure, having the facilities of a real school at hand maybe "handy", but I don't see it as a requirement for the survival of the "art". What is required is a couple of loonies like myself and a lot of fellow members of APUG , that are both willing to learn and never get tired making their way through yet another bunch of new photography facts, figures and instructions... I think we call that a "hobby" in most peoples' vocabulary, but the distinction between hobby, art and a real job is as thick as a sheet of film in photography...

Marco B said:

What is required is a couple of loonies like myself and a lot of fellow members of APUG , that are both willing to learn and never get tired making their way through yet another bunch of new photography facts, figures and instructions...

Click to expand...

One thing that would be very useful here would be a calendar function. Post the workshop on the calendar, and link the discussion to it.

Searching for workshops is near impossible on the search engine.

1.--there is apparently a thing called albert reversal where the dichromate treatment DESENSITIZES the previously sensitized crystals and you have a "negative" latent image which can be developed to a positive after exposing the rest of the silver---apparently this is only with physical development--I tried it with developer and it's just way too powerful and gives total fog---or pure fog with the very light inverse latent image over it---I'm gonig to try with silver nitrate intensifier.....when I decide to get dirty.

ON THAT!!!! I'm certainly interested in making film/plates/paper----just not yet---and this is the type of thing that really lends itself to the cookbook treatment---THIS is the type of cookbook for photography that needs to be written--that I would buy---(I have the other cookbooks...I'm jst saying)...people want to try themselves first---at their own pace..in their own time...

before i start, you can bet I'm going to copy down every recipe I see here and start cooking---no classes at all....just watch what I can on youtube...and read and educate myself...the people here who wooud make their own batches seem like the kind of diy people who dont' got to classes--they want to do it themselves--see how many build cameras....and then find out that the expensive camera they were trying to avoid buying is actually pretty cheaply priced compared to time involved in making one.

COOKBOOK...or maybe somebody can organize the posts like that...heirarchial recipies...like a huge electronic database of recipe cards...look for what you want to do and see how many ways and variations to do it....that is how to encourage this type of diy film/paper making in my opinion. At least that would work best for me.

Many thanks for your replies, i was mainly curious as to what would happen. When i get the chance i will give it a go merely because I am curious to see what the result would be (expose, bleach in the dark, rinse, dry, wind back into cassette, load, shoot a 400 at say 50ISO, then develop. Or try it with paper. Blue-sensitive is quite intresting! I hadnt thought of the sensitizers and other stuff. Gotta love curiosity, not that i would ever use this in practice! When i next get paid i intend to buy a copy of that book, will be a very intresting read indeed!

Areva recycles Nuclear fuel for reuse in several locations world wide.

But that isn't the point of this thread, as to PE's comment about so few wanting to learn, I do not believe that is true. I for one have plenty of desire to learn, but lack that other precious commodity of time. I use a lot of time learning, but I do not have the time to travel to the places I want to go to learn more. Someone once said "I have only seen further because I stood on the shoulders of giants". That person never named the giants, it is my hope that some day the names of many people here are remembered as those giants of photographic process some day.

I know I have learned much form people here, that were willing to help me do things right, and when on more than occasion looked at my photos and said to myself "what did I do wrong this time".

Thank you.

On the original topic, wouldn't re activating the silver yield a ghost of the original image or wash a large portion of the silver off the media leaving an even more lousy even slower film or paper? I have to believe that there is no way that just by bleaching washing and drying you would retain 100% of the silver, not only that, but what would that silver be suspended in, I have to also believe that a lot of the gelatin would be lost as well. This would have to combine with the loss of sensitizing dies would combine to really ruin the original emulsion.

johnielvis said:

ON THAT!!!! I'm certainly interested in making film/plates/paper----just not yet---and this is the type of thing that really lends itself to the cookbook treatment---THIS is the type of cookbook for photography that needs to be written--that I would buy---(I have the other cookbooks...I'm jst saying)...people want to try themselves first---at their own pace..in their own time...

before i start, you can bet I'm going to copy down every recipe I see here and start cooking---no classes at all....just watch what I can on youtube...and read and educate myself...the people here who wooud make their own batches seem like the kind of diy people who dont' got to classes--they want to do it themselves--see how many build cameras....and then find out that the expensive camera they were trying to avoid buying is actually pretty cheaply priced compared to time involved in making one.

COOKBOOK...or maybe somebody can organize the posts like that...heirarchial recipies...like a huge electronic database of recipe cards...look for what you want to do and see how many ways and variations to do it....that is how to encourage this type of diy film/paper making in my opinion. At least that would work best for me.

Click to expand...

The book is being written. It is harder than I thought. HOWEVER...

There are about 100 - 200 Photo Engineers world wide and they are all probably over 65 with many over 80. Therefore, we will not be around long enough for you to get interested enough to actually take a course, and this type of work, quite frankly, is like painting. You don't really learn it by watching TV. You learn by having someone teach you while leaning over your shoulder and coaching you to learn good techniques.

But yes, time and money are factors in all of this. It is difficult to just give a course. If it is on the west coast, I have a huge box of materials to ship, and I have to travel, but if it is here, you have to travel. It is a conundrum.

But, there are not many left to teach nor are there many who wish to teach. And, published formulas generally give you only 1/2 of the story if you go to the early literature. In fact, I have not seen a clear, fully articulated formula in any publication but the two I have made here.

And even there, I was not a master of clarity, I must admit, but at least a few people from APUG duplicated the results. The real information comes in "why" things work as they do, not what to do.

PE

GOOD----so a book is in the works---you know--you may NOT want to wait till it's perfect--it will never get done that way--if you have 80%, then put it out there---I will buy it---I will buy your manuscript right now just to have somethign to pick up...a book is much different from a computer screen---you can mark things...I'm of the different generation--books help me.

if the first version ain't perfect so what--just update--second editoin, etc...printing is easy and fast and cheap now---I'd prefer a book even to an online book--well--I'd print it out anways.

but this type of work--I beleve, needs just to be documented---people don't really need all that much guidance -- those that really want to learn--just a place to start---they will learn by doing themselves---classes are for people who want to be shown...books, notes, scraps...are for people thirsty for knowledge so they can DO. or is this just me? Everything I've ever learned has not come from somebody teaching me...it has come from interest, doing, failing, finding out why I failed from INterest--not giving up.

PLEASE--publish---soon---you can get hit by a car...lightning...etc...I told the same to burt saunders with his graflex knowledge...he's old...he can drop any minute--and he KNOWS how to do this stuff like nobody else. it'd be a shame to let this knowledge slip because of timing---

and timing is the main issue--when I retire in 10 years, I'll have all the time in the world to putter around and even travel to learn things...now I gotta earn a living, so the hobby comes second...close second though....but now...something to look over...to read over and over--that will give me something to have on my mind...to "sleep on"...then one day---I see something...a lightbulb goes off with an "I can do this"...and then I do. It's all about timing. Classes are fixed in time...books are timeless.

Please do not delay with the book--

hey---contact me--I'll send you a payment right now if you send me a photocopy of your notes or a pre-press book version--something useful, you know. reasonable price of course, you know...