[alt-photo] Re: Question for Platinum/Palladium printers

[Don Bryant]

>
I cannot for the life of me understand why people insist on trying to 
clear Pt/Pd prints in ... citric acid
>

Because it works! Do you have proof that citric acid doesn't?

FWIW I move the developed print directly into the 3% citric acid bath sans
water rinse. Followed by a second citric acid bath, both for 5 minutes.
Fresh for each print

Quoting Carl Weese -


"After the print has been washed for five minutes, it's ready for clearing:
we need to get rid of the iron left by the light-sensitive ferric oxalate.
There are several ways to do this, the traditional one being weak baths of
hydrochloric acid-not my cup of tea. What I use is a first bath of a freshly
mixed solution of citric acid in warm water. The print stays there for ten
minutes, with occasional agitation. Agitation and timing are not critical
the way they are in fixing silver materials. If I'm tied up doing something
else when the ten minutes are up, it doesn't hurt to go longer. I use just
enough solution to fully cover the print, and mix fresh solution for each
print. The sheet is next rinsed and transferred to a second clearing bath,
this time a combination of EDTA disodium (a chelating agent) and that old
photographic standby, sodium sulfite. The print finishes clearing in just a
couple of minutes in the second bath, but I give it ten as a safety factor."

Note that I as I mentioned above I don't follow the developer with a water
wash. Same procedure for Kalitypes.

One of the reasons quoted for early practitioners using HCL is that it was
economical. Citric acid was very expensive because of it's limited use in
the food industry unlike it is today.

I don't have residual staining with my prints. A hundred years from now who
knows. I have seen Edward Weston platinum prints in museums that are
obviously stained, made in the early teens in the 20th century so who knows
how he cleared his prints.

A local friend of mine has given me a couple of his palladium prints that
have become stained over time so the appearance of stain seems to occur or
can occur relatively quickly. 

I also know Bob Herbst recommends 1% hydrochloric acid for clearing so I
don't dispute it's effectiveness. I do tend to agree with Loris about it's
potential negative effect on paper fibers.

 

I don't think there is any authorative source about staining. I don't regard
Ron Mowery, aka PE on APUG, as an expert regarding clearing of pal/plat.
prints, though certainly knows a lot about photo chemistry.

As for using Lime-A-Way and other rust stain removers, it will work though
how effective it is for all papers I can't say.

Regards,

Don Bryant