Re: mordancage

[Judy Seigel <jseigel@panix.com>]

It isn't clear to me why it's necessary to search for bomb grade peroxide,
or anything stronger than drugstore for that matter -- simply "adjust"
the strength of the bleach by increasing ratio of peroxide to water. That
is, more peroxide, less water equals stronger mix.

The reason, incidentally, that highlights in the method of fluting a
photograph that seems now to be called "mordencage"  don't soften stems
from the basic principle of the process: The bleach of peroxide and either
copper sulfate or copper chloride destroys/ attacks or softens metallic
silver.

Metallic silver is the BLACK part of a developed photograph. The
highlights (whites) have no metallic silver, hence no action.  In the
bleach and redevelopment method the entire photograph is removed, and the
silver halide remaining (before fixing) is then developed up -- in reverse
of the first print, of course.

Judy


On Tue, 21 May 2002, Christina Z. Anderson wrote:

> Hi Cor!
>      It is 20 or 40 *volume*, which is (if I figure it correctly
> mathematically) is somewhere around 6-12%.  I divided volume by 3.4 (is this
> right?)  At any rate, I get it from a beauty supply place in a concentrate
> of 135 volume and dilute with water accordingly.  You can also buy a gallon
> of 40v for very cheap--maybe $6.  It doesn't really matter what volume of hp
> you have--it just works faster the stronger it is.  I have not experimented
> with less than 20 v as some on this list have (the standard 3.5% drugstore
> type would be 10volume and Judy and others say that works fine).
>      Any formula yellows/browns fiber paper as far as I can tell at the
> moment.  I noticed this last time that it was able to be rubbed off.  With
> RC paper you do not get this staining of the highlights.  I have been
> experimenting with Forte Polywarmtone Elegance fiber and RC, Ilford coldtone
> RC, Ilford MGIV glossy...I think that is it at the moment.  The RC paper
> really works the best and doesn't stink as badly when it is dry :)
>      As a general rule, when I am printing an image I will print an extra
> one or two in RC and fiber, to be available to mordancage later.  Thus I
> have a stack I can continue to experiment with at the moment, and will
> continue to test this yellowing thing more.  Jon Bailey I'm sure could also
> share his comments on this.
> Chris
>
> > Thanks for the interesting post, Christina,
> > but..
> > "Christina Z. Anderson" wrote:
> > >      First of all, you can mix up the formula and let it sit for months
> and
> > > it keeps on tickin'.  (1000 ml water with 30g copper chloride and 80ml
> > > glacial acetic acid).  Just before use, mix it with 20v or 40 v hydrogen
> > > peroxide, equal vol.
> > ..I assume with 20v or 40v you mean % hydrogen peroxide? If that's the
> > case that seems like a lot of peroxide, and a hughe difference (20%
> > versus 40%) as well?
> > Another question: in the past we discussed the yellowing of the
> > highlights after re-development when using FB paper. You get these also
> > with this bleach/developer combo?
> > Thanks and best,
> > Cor
>
>