Re: Stain from sodium metaborate


Judy Seigel (jseigel@panix.com)
Mon, 18 Oct 1999 17:45:43 -0400 (EDT)


On Mon, 18 Oct 1999, Lukas Werth wrote:
> .... I am
> actually not sure whether the remaining tinge in the highlights is from the
> sodium metaborate, and I am not enough of a chemist to find out.
> But I would like to make sure that there is nothing apart from the gold
> left in the paper base once I am finished with the print, therefore my
> question:
> is there a recommendation of how to make sure to remove the sodium
> metaborate, of a test which shows whether something is left?

This comment may be chemically naive, but... for what it's worth: Assuming
my chemistry isn't backwards, and the sodium metaborate is to make the
emulsion more *alkaline* -- I did a series of tests adding alkali to
glyoxal, as it's claimed this will preserve & strengthen links in the
gelatin. Some 4 or 5 that I tried turned the paper/gelatin a shade of
orange, except baking soda... sodium bicarbonate, which left no residual
stain.

Possibly worth trying (unless you want acid, in which case, sorry, I can't
help you).

Judy



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