Different source of black spots from palladium-platinum prints

From: Bob Kiss ^lt;bobkiss@caribsurf.com>
Date: 02/22/04-08:31:53 PM Z
Message-id: <NIBBJBPKILANKFOAGNHEGEIBCJAA.bobkiss@caribsurf.com>

DEAR DON,
        Thanks so much for posting this fix for black spots...I have been searching
for one. I have been thinking of posting my observations as to the source
of black spots on my Pt/Pd prints in order to help others and your posting
has prompted me.
        I have never had black spots from my metal rotary paper trimmer or from
precipitates in my Pt or Pd solutions (at the ambient temp of 80 F they
don't precipitate). I HAVE had black spots resulting from Ferric Oxalate
precipitating around the threads on the top of my brown bottle. It appears
that our FO solutions are so close to saturation that the FO seems to dry
into a crusty powder around the threads and top rim of the bottle and fall
into the solution. These pieces are picked up by my eye dropper, mixed with
the Pt & Pd solutions and cause these "chawming" black spots. Before every
use I carefully wipe the edge and threads of the bottle and dropper cap
clean (being certain to start inside and wipe outward in a circular motion)
with cotton soaked in distilled water and I no longer get spots. If I
forget to do it...Wham! There they are.
        I hope this will help those who have tossed away their rotary cutters and
filtered their Pt & Pd solutions and STILL get those spots.
                        CHEERS!
                        BOB

-----Original Message-----
From: Don Bryant [mailto:dstevenbryant@mindspring.com]
Sent: Sunday, February 22, 2004 1:23 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Getting rid of black spots from palladium-platinum prints

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

--------------%<-------------------------------------------------------

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.

--------------%<-------------------------------------------------------

I havenít tried this myself but it sounds reasonable.

HTH,

Don Bryant
Received on Sun Feb 22 20:31:32 2004

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