RE: Cyanotype toning and lead acetate.

Hi Judy, I tone according to the info in your article. I mix fresh
bleach for each session, I use the same tannic acid for at least 4 - 5
sessions (filtering sediments - it works fine even if it gets dark with
time) because mixing tannic acid is a PIA (takes long and it's messy).

Just a clarification (in case of a probable misunderstanding):

Citric Acid bath that I mention is done after processing (development)
in tap water and before bleaching / toning. If I don't clear in Citric
Acid, the image will fog (most noticeable in the highlights - low
contrast, poor tonal separation, no clean whites). My take is: this is
due my alkaline wash water; without clearing in citric acid I can't get
rid of unexposed iron sensitizer (it becomes insoluble / trapped in the
fibers) and when I tone such not cleared prints, the remaining iron
somehow interacts with the toner and cause the problems mentioned above.
<- This is image stain, there's also non-image stain if your tannic acid
is too strong and/or your paper is not adequately sized. For instance,
the back (relatively rough compared to the front) of COT320 stains
heavily regardless you use fresh solutions or not - but the front side
remain clear (albeit slightly warmer when compared to unprocessed
paper). That's probably because the front side is surface sized also.
These two types of staining (if you like) are completely different and
unconnected to each other.

Regards,
Loris.

-----Original Message-----
From: Judy Seigel [mailto:jseigel@panix.com]
Sent: 21 Nisan 2006 Cuma 08:28
To: alt-photo-process-l@usask.ca
Cc: alt-photo-process-l@sask.usask.ca
Subject: Re: Cyanotype toning and lead acetate.

...
We never used a citric acid rinse, ever, and got perfectly clear whites
-- IF
THE BATHS WERE FRESH. Many of our combos (from memory again) gave much
better color WITHOUT a rinse between -- so we'd mix up a huge beaker of
the tannic acid & another of the sodium carbonate bleach, and pour just
enough to cover the wet print... then dump after use.
...
Received on Fri Apr 21 08:38:32 2006