Reversal Processing

[mrred]

For the reversal, try the following bath of 2 minutes instead of light:
Water 1L
HCl 37% Solution 1ml
SnCl2 1g
It is important to make the solution acidic prior to adding the SnCl2, otherwise you will get Sn(OH)2 which is not water soluble.

I have used this in some reversal processing I am working on. I think Acetic Acid can also be substituted, but I have not worked out the amount for this.

The articles I read was to make the SnCL2 part of the second developer. Check this thread out. http://www.apug.org/forums/forum37/8...l-foggant.html

Having a seperate solution to do that could be handy. How many uses could it get?

[mrred]

Thanks Mrred,

I get into too much trouble if all the gin & tonic ice has been used in the darkroom in hot weather, when my priorities are called into question

It makes an interesting chemistry class!


On the note of the strength of your bleach.... You only need it string enough to clear the developed silver. I use 6g / liter of Dichromate. It has reduced the amount of image floating down the drain.

I also use a reduced clearing bath. I use 30g/ liter of sodium metabisulfite. The indicatorcator is black spots in the highlights. This is actually chrome deposits from the bleach. First fix would to ensure thorough wash before the flash is done and if still a problem, increase time in the clear.

If the clear has any more than a slight change of colour, you need more washing on the bleach stage - there is too much bleach carried over.

[Photo Engineer]

Stannous Chloride reversal baths go bad rather quickly and therefore if mixed with developer would reduce the lifetime of the developer. If you have softness issues, it is fair to add a Chrome Alum or Aldehyde hardening bath before the bleach and if you do, surround it with good washes.

PE

[johnielvis]

I've been using longer bleach times and more dilute bleach these days---no more than 2g/litre of dichromate and like 3' bleach times.... any less than 2g/l and you start to get chemical exhaustion problems--it still works, but the times go WAY up...3' is about my limit of bleach times.

anyways--never had an emulsion peel off with that brew yet.

[Sankt.Ahlomow]

Hi Joe,
try this:

http://home.snafu.de/jens.osbahr/pho...r_reversal.pdf

It works very well.

Regards,
Thomas