Getting rid of black spots from palladium-platinum prints

The following message was posted on the Bostick & Sullivan Web Board
recently by Kevin Sullivan.

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Michael Mutmansky shared his technique with me for removing those
dreaded black spots that sometimes happen in platinum and palladium
prints, usually caused by little bits of metal in the paper. It can also
be used on broader areas, like border areas that have a touch of fog.

Michael devised this system after reading a passing reference to it in
The New Platinum Print, I think. As far as I know, he is the first
person to try this in the modern era, although it was known about at the
turn of the century during the classic platinum printing period. A few
folks have tested it and found it to be very useful, you can remove
black spots or stains and then retouch the image back up to the proper
tonality.

You will need very small amounts of hydrochloric (also called muriatic)
acid and regular household laundry chlorine bleach. Hydrochloric or
muriatic acid can be purchased at hardware stores and swimming pool
supply places, it is used to clean driveways and other concrete
surfaces.

Get a couple of small 1oz (30ml) bottles. Put 20ml of distilled water in
the bottle and add 5ml hydrochloric acid. In a separate bottle, to 20ml
of distilled water add 5ml of bleach. It is important never to mix the
stock solutions together directly, especially in concentrated form.
Diluting the acid and bleach with water is partly for safety, partly for
better control of the bleaching. [Read my safety warnings after the
instructions]

Set out a capful (or small container of some kind, you won't need much)
of the acid solution and a second capful of the bleach solution. In
between the two place a dish of clean water for rinsing your brush.

Find a finished print with a black spot. Use a fine natural fiber brush
and put a small drop of the acid solution on the black spot, it won't
take much and you don't want the solution to spread farther than your
spot. Rinse the brush in the clean water, then dip the brush in the
bleach and lightly touch the bleach to the same area to which you had
applied the hydrochloric. Almost immediately the spot should start to
dissolve away. Repeat the steps if necessary, each time the spot will
get smaller. Always rinse your brush in between the acid and bleach
steps.

When done, wash the print again for 10 minutes or so to remove left over
chemicals. When its dry you can spot the areas back in, if needed.

ULTRA-PARANOID SAFETY SPIEL: This works because you are actually
reacting the acid and bleach together to make PURE CHLORINE GAS (almost
the only thing which will dissolve gold/platinum/palladium). In small
quantities chlorine is fairly harmless, as we know it is used in
drinking water, swimming pools and laundry without any problem. But
NEVER mix concentrated bleach and acid together directly! PLEASE. That
could result in large quantities of chlorine gas being generated, and is
very dangerous. Always work in a well ventilated area, just the bleach
alone is going to smell pretty bad. This system is perfectly safe if you
follow these directions, but do not 'improvise' or think that mixing it
stronger will be of any benefit. Just a little is all that's needed. If
you don't understand why chlorine gas is dangerous then just don't do
this! This is why its important to rinse the brush in between each dip
in the bleach or acid, you do not want cross contamination. Plus, your
brush will last longer (the reaction will destroy the brush fibers). Of
course, be careful when handling containers of acid or bleach, don't
drop them or spill them, and do not store them next to each other.

Aside from that, I have to give Michael credit for working this out.
This is a great trick which pretty much eliminates one of the
reoccurring troubles in platinum printing. I used to figure that there
wasn't any way to effectively remove the spots, since they are just as
archival as the pt/pd. But this is a simple system that will save a lot
of prints that are fine except for that one annoying spot.

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I haven't tried this myself but it sounds reasonable.

HTH,

Don Bryant

 
Received on Sun Feb 22 11:23:19 2004