Topic: bleaching with household bleach

[vitaminaR]

ola fellow filwasters!
i have tried a new experiment and wonder if any of you got any input for me.
yesterday i tried household bleach to bleach some little fb b&w prints i have. the emulsion does come off nicely, especially if you dilute it quite a bit [if straight, the image disappears almost instantly  ]. problem is i don't know how to fix the image properly. i also am out of fixer and i am away from the "city". does SALT help at all? does anybody know anything  about this
thanks in advance for your expert advice.
r

[Francois]

Salt won't do much.
As far as I know, you don't need to re-fix images treated this way. But you do need to re-wash them properly. Bleach is a strong alkali and could damage the image in the long term.

This technique is mostly recommended for localized bleaching and removing pinholes from prints... but reducer is preferable.

[LT]

I'm not really sure what you are acheiving? You say the emulsion comes off? Once that happens, surely all you left with is a piece of blank paper.  is that what you wanted? I wonder what use a piece of baryta paper with no emulsion is?

[LT]

Steady on there Rosanna - no one is calling you stupid. Now are we getting to crossed purposes by the term "emulsion"?  Now I understand the term emulsion to mean the gelatine layer that sits on top of the paper base and holds the image forming silver halides? So are you saying this whole layer is being removed by the bleach?  I also often use bleaching process but use ferricyanide - this doesn't do anything to the emulsion, but it does alter the developed silver in the emulsion reducing it and preparing it for redevelopment. If you are removing emulsion you'll get holes that you can see the paper base through - is that what you want? If so you can do it bytaking the paper soaked in cold water, then place it in really hot water causing the emulsion to blister and if left long enough, it will lift entirely.

If you are talking about reducing the silver to lighten the print then wanting to make it permanent,  why not refix in a plain hypo solution?

[Heather]

Neutralising won't "fix" the image if you're using pot. ferri. to bleach back. It'd help stop the bleaching process but to actually fix the image you need sodium or ammonium thiosulphate.

The expensive way of getting sodium thiosulphate would be to buy the cheapest pet fish declorinator you can buy. That tends to be pretty pure sodium thiosulphate. The Tetra brand "aqua safe" stuff apparently doesn't have this so that might be a lost cause. BUT you can buy vials of this white powder from Wilkinsons shops here in the UK. IIRC it's around ?3 for a small vial which won't mix up a lot of fix but it does say it's sodium thiosulphate on the packaging.
The other cheaper/larger amount place where you find sodium thiosulphate is swimming pool supply shops, as a declorinator after you add lots of chlorine to a pool to clean it out.

[LT]

Ok - sorry for the confusion

Right - salt water can aid washing ... so I suspect what you are seeing is a better washing action in the prints you've placed into salted water.  The image wont be fixed, and I should imagine it will develop out at some point if the household bleach has the same effect at the pot-ferri bleaches, but the print is washed better so there is less/ no residual bleach in the paperbase acting on the silver as in the non-salt washed one.

I expect that using an acid will only stop the bleaching, not fix the image.  You really need to get some kind of fixer as Heather says.  I've no idea as to household things that will help - maybe ask over at apug.org.  There are plenty of very knowledgeable chemists over there.

[Francois]

I went through an old book and this is the only reference on the subject I could come across.
Ref.: Petersen's Big Book of Photography, edited in 1977. section 22 basic retouching techniques, p.431

As far as I can tell, chlorine will remove the silver from the image. But this process doesn't need fixing since it doesn't work on the same principles as Farmer's reducer. A strong alkali will soften the gelatin emulsion and the bleach will oxidize the silver at an accelerated rate (causing fading). Fixing again won't stabilize it any more. An acidic bath will stop the chlorine action but will also cause the release of highly toxic chlorine fumes (this is basically how gas chambers worked... a very bad thing) so I would not recommend it (even if the concentrations are very low, better be safe than sorry). Just good long wash in plain water should suffice. And also working in a very well ventilated area would be highly recommended since we don't really know what reaction the bleach will have with the chemicals in the emulsion...

Hope it helps clear this out...


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[LT]

Interesrting stuff Francois. Thanks for that. I take it clorox is a brand name for household bleach?

So it seems Rosanna's problem here is in washing out the bleach sufficiently.

As an aside, tincture of iodine can also be used as a reducer, but this does need fixing after use - to both stabilise & remove the yellow stain.  

[Francois]

Yep, Clorox is a household bleach. Though I don't know if it works the same with the products that have color-safe additives.

Regular Chlorine Bleach is a solution of approximately 3?6% sodium hypochlorite (NaClO).

I know it also works on RC prints.