RE: Cyanotype toning and lead acetate.

On Fri, 21 Apr 2006, Loris Medici wrote:

> 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

Hi Loris,

I think I understood that... but IME wasn't necessary. The difference
could be the water -- maybe yours is more alkaline, or the timing, or
whatever. But as I found in the tests I described in P-F #7, it didn't
happen if I did it the way I said & didn't do it the way I did it before I
did it the way I said didn't do it.

An interesting test of course would be to try the conditions that gave me
the flat tones, poor tonal sep, no clean whites you mention -- but WITH
the bath you describe. And see if that prevented them here in NYC, or only
in Turkey.

(Tho I used a different paper, another variable...)

best,

Judy

> 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.
Received on Fri Apr 21 14:59:51 2006