Paper's and Fog

Kmurphy220 · Apr 30, 2017

So hypothetically speaking, what exactly would one do if they accidentally partially exposed papers to light. This hypothetical has obviously nothing to do with me, but just for a friend. Say that it was visible on the top paper most, but barely on the middle part of the stack. In theory would it work like Harmon DPP where a pre-flash eventually goes away due to some photon light stuff, or would this so called person be SOL and need to buy more paper?
Thanks, for a friend.

dE fENDER · May 1, 2017

The recipe how to restore fully fogged paper several times was published in russian photo literature (perhaps in some english too). For example - Sovetskoe Foto, 1987/02, p. 41. You need to rehalogenize it. For the most modern paper it doesn't cost wasted time, but there are some old paper, on which it makes some sense to try.

Processing solution:
* Potassium dichromate - 2.5 g;
* Sulfuric acid - 5 ml;
* Potassium bromide - 1.2 g;
* Water - up to 1 l.

Process for 2 min in the solution at 18 C, then wash for 20 min and dry. The paper should have uniform fog (for the whole sheet) and the sensitivity will fall from 2 times (for fresh papers, fogged only for short period of time) to 100+ times (old papers).

You can try to hypersensitize the sheets also.

bdial · May 1, 2017

Tell your friend that if the fogging is only on part of the sheet, the easiest thing would be to use the unfogged area for either test strips and prints, or small prints.
Perhaps for the middle, just live with a black edge along the border.
If the fogging is slight, then a restrainer like Benzotriazole may do the trick.

Oh, and tell your friend that he should check, then double-check that the paper is covered before turning on the lights (BTDT), think of it as a learning experience.

Gerald C Koch · May 1, 2017

The problem with rehalogenizing paper is that any sensitization dyes may be washed out.

jvo · May 1, 2017

don't know about your friend, but my friend has really screwed up a bunch of stuff in the darkroom... I, eeerrrr, he has made all kinds of mistakes i wouldn't begin to count!!!!!

Gerald C Koch · May 1, 2017

Kmurphy220 said:
In theory would it work like Harmon DPP where a pre-flash eventually goes away due to some photon light stuff, or would this so called person be SOL and need to buy more paper?
Thanks, for a friend.

There is a big difference in the amount of exposure between pre/post flashing and exposing the paper to room light. In addition there is a difference in the positive effects of flashing which are lost quite rapidly and fog which does not go away.

Craig75 · May 1, 2017

if it's fogged you could still try messing around doing different looking prints

this guy has done a whole book of expired film and old fogged papers.

http://www.olivierpin-fat.com/Books 3.html

not to everyone's taste but it could be opportunity to see what you can conjure from circumstances

Kmurphy220 · May 1, 2017

Haha. Thanks everybody for the replies, I'm sure my friend will be very appreciative of this knowledge. I'll probably end up recommending the test strip idea, or maybe usage in a pinhole camera. Hopefully he recovers from such a dumb mistake, and will also order some more adorama paper....

Photo Engineer · May 1, 2017

dE fENDER said:
The recipe how to restore fully fogged paper several times was published in russian photo literature (perhaps in some english too). For example - Sovetskoe Foto, 1987/02, p. 41. You need to rehalogenize it. For the most modern paper it doesn't cost wasted time, but there are some old paper, on which it makes some sense to try.

Processing solution:
* Potassium dichromate - 2.5 g;
* Sulfuric acid - 5 ml;
* Potassium bromide - 1.2 g;
* Water - up to 1 l.

Process for 2 min in the solution at 18 C, then wash for 20 min and dry. The paper should have uniform fog (for the whole sheet) and the sensitivity will fall from 2 times (for fresh papers, fogged only for short period of time) to 100+ times (old papers).

You can try to hypersensitize the sheets also.

This will absolutely NOT work. The mix will turn the silver into silver sulfate which dissolves in water. Please use Potassium Ferricyanide instead.

PE

RauschenOderKorn · May 2, 2017

Similar problem, different solution:

(there was a url link here which no longer exists)

Other option:

There is a current article in a German photo magazine about blixing, washing, drying and ironing paper and then using it for "Fine-Art" inkjet prints. If you are interested I can look it up for you.

RauschenOderKorn · May 2, 2017

dE fENDER said:
The recipe how to restore fully fogged paper several times was published in russian photo literature (perhaps in some english too). For example - Sovetskoe Foto, 1987/02, p. 41. You need to rehalogenize it. For the most modern paper it doesn't cost wasted time, but there are some old paper, on which it makes some sense to try.

Processing solution:
* Potassium dichromate - 2.5 g;
* Sulfuric acid - 5 ml;
* Potassium bromide - 1.2 g;
* Water - up to 1 l.

Process for 2 min in the solution at 18 C, then wash for 20 min and dry. The paper should have uniform fog (for the whole sheet) and the sensitivity will fall from 2 times (for fresh papers, fogged only for short period of time) to 100+ times (old papers).

You can try to hypersensitize the sheets also.

How does the complete process work? Is there a need to uniformly fog and develop and then rehal-bleach or do you rehal-bleach the undeveloped paper? How does Hypersensitization work?

Doremus Scudder · May 2, 2017

See what you can salvage first. I've inadvertently exposed paper to white light and lost only a few sheets; interior sheets had some edge fogging but were usable with large borders and a bit of trimming.

If there is nothing to be save, then chalk it up to tuition to UHK (University of Hard Knocks) and buy new paper.

Best,

Doremus

newcan1 · May 11, 2017

When you rehalogenate fogged paper, is it necessary to develop it normally before bleaching, or do you just bleach under safelight conditions without prior development?

Gerald C Koch · May 11, 2017

newcan1 said:
When you rehalogenate fogged paper, is it necessary to develop it normally before bleaching, or do you just bleach under safelight conditions without prior development?

Please read post #4. The rehalogenated paper will not behave as expected and will probably be mush slower. If it was VC will lose this property.

newcan1 · May 12, 2017

Gerald C Koch said:
Please read post #4. The rehalogenated paper will not behave as expected and will probably be mush slower. If it was VC will lose this property.

I understand this. My question relates to the rehalogenation process. In order to rehalogenate, can you simply bleach fogged but unused paper in a rehalogenating bleach, or must you develop it (to bring out the fog) first? I get that it will be fixed grade and much slower afterwards.

Paper's and Fog

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