Liam Lawless (lawless@vignette.freeserve.co.uk)
Fri, 29 Jan 1999 04:18:51 +0000
Hi Steve,
Sorry for late reply - afraid your last message got overlooked!
Shadows are more or less OK, highlights thin: indicates correct exposure and
underdevelopment (just as you said!) Bleaching and redeveloping with PMK
might cope, but depends how thin your highlights are; best to test first on
a neg that doesn't matter too much.
What you want, ideally, is to increase highlight densities without affecting
the shadows too much, but most intensifiers are fairly proportional, so you
might need to be sneaky. Monckhoven's intensifier increases highlights and
cuts the shadows at the same time, but involves the use of mercuric chloride
and cyanide. Most of the powerful intensifiers are very toxic, but a
not-so-toxic chromium intensifier can be made up to give slight, medium or
strong intensification, and one way to use it to intensify just the
highlights would be as follows.
Start with a halogenising bleach (turns silver into silver halide, e,g. the
bleach that comes with a sepia toner ), and dilute it to maybe a fifth of
its proper working strength so that it acts extremely slowly on your
negative. What you want to do is use it to bleach very lightly, so that
just the shadow densities and light midtones are affected. After this, wash
and then bleach to completion in the chromium intensifier, then wash again
and redevelop in a print developer.
The idea here is that intensification occurs only in those tones that were
affected by the chromium bleach. A chromium intensifier bleaches the silver
image to silver chloride and also puts down some insoluble chromium compound
(which is how it intensifies) whereas the sepia bleach just turns the silver
to one or other of the silver halides (usually silver bromide). The
redevelopment stage turns all the silver chloride and silver bromide back to
silver again, but the chrome bleach has in addition deposited chromium
something or other in the highlights. Bingo!
There are other intensifiers that could be used this way as well as
chromium, but I'm guessing that you don't want to mess with mercury, etc.
If you need a great deal of intensification, copper and silver is very
powerful, but also raises fog levels quite considerably.
If you can borrow or steal a copy, Clerc's Theory and Practice goes into a
lot of detail. In fact, I've just looked at my copy and I see there's a
section on intensification by bleaching with chromium and redeveloping with
pyro, which, as you probably know, is related to what I'm doing at the
moment (so thanks, Steve!)
Clerc's recipe for the chromium bleach is:
Part A: Pot. dichromate, 10% solution
Part B: Hydrochloric acid, 10% solution
I doubt if you'll get enough dichromate to dissolve to make a 10% solution,
so maybe Clerc's dichromate was different to mine. Use a saturated solution
if 10% won't dissolve.
For weak intensification, use 20 parts A, 40 parts B and water up to 100
parts.
For medium, use 20 parts A, 10 parts B and water up to 100.
For strong, use 10 parts A, 2 parts B and water up to 100.
Then again, you can probably buy it ready made, but that doesn't give you
any control.
Clerc says to use boiled water, but mine works OK without. Work under
artificial light, and do not allow negs to stay in the bleach longer than
necessary.
It is probably a good idea to harden your negs before treating them.
My advice is always to try the simplest method first, but come back if you
want more recipes.
Liam
-----Original Message-----
From: Steve Shapiro <sgshiya@redshift.com>
To: lawless@vignette.freeserve.co.uk <lawless@vignette.freeserve.co.uk>
Date: 27 January 1999 04:10
Subject: Re: Amidol Redeveloper
>Liam,
>
>My intention is to redevelop negatives that were developed late in the day
>using weak solution. They didn't come out with enough intensity, but all
>the detail is there.
>
>I guess what I want to do is make duck soup out of old duck bones. In this
>simile, I turly mean to say the detail, the information is all developed;
>but the negative is too thin to do the image justice. I was thinking of
>selenium, or an intensification formula.
>
>Do you have anyexperience with any amidol film developing formulas?
>
>Steve Shapiro, Carmel, CA
>sgshiya@redshift.com
>'the dude abides'
>
>
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