> After coating and drying the paper is run through the
>process with no exposure and there is a definite "pink" cast to the emulsion
>area after clearing.
I had trouble with pink prints a couple of weeks ago that may be relevant, but
if not, is a curiosity which I found interesting.
I had mixed some size at home and allowed it to set as preparation for a
workshop elsewhere. I sized the paper at the workshop as part of the
demonstration. The paper was then coated with a platinum palladium mix and
exposed. When the paper came from under the lamp the whole of the surface had
turned bright pink, i.e. both the picture area and the surrounding sized but
unsensitised paper. After development in potassium oxalate and clearing in EDTA,
the picture area, i.e. the area that had been sensitised, gave a normal platinum
palladium print with good whites and a full range of tones and no discoloration
but the area that had not been touched by the sensitiser remained pink. Very
pretty if you like that sort of thing !
We made fresh size for the participants on the workshop and everything worked
beautifully without a sign of pink.
The prepared size had been carried in the boot of the car with materials for
platinum and gum printing but also in the presence of a large transport
container of ferric chloride which had some minor dried dribbles around the
mouth.
My conclusion was that the pink had resulted from iron contamination from the
very small amount of ferric chloride around the stopper of its container. The
gelatine had been carried in an open Pyrex jug with a cloth over the top whereas
all the other chemicals were in tightly sealed containers.
The explanation of the final print appeared to be that the platinum had acted as
a catalyst in enabling the EDTA to clear the iron in the picture are but that
where there had been no platinum, outside the picture area, the iron
contamination, and thus the pink, remained.
For DKenn, a bath in EDTA could get rid of the pink.
Terry King