On Wed, 19 May 2004 wrleigh@att.net wrote:
> Judy,
>
> When you say the emulsion is too fresh, you said this is the A & B
> themselves. By this I assume you mean that A & B should be mixed and
> then let the bottles sit on the shelf for at least 3-4 days and not use
> them immediately. True?
Yes... we did this as a class project, testing every day supposedly for
the semester... but organization and resolve dissipated . I had found the
initial wash-off in my own studio & thought it would be instructive to
discover the rest... Another variables project was differences in d-max &
clearing when the emulsion has been coated on the paper and stored for a
day, a week, a month (which probably varies by paper, students tested
their own usually).
As for changes in the emulsion as it 'ripens," I found that tones were a
bit lighter and times about 25% longer after several years.... and that
scale improves for about the first week... (Inbetween the first week and
several years, I have little data.)
> Following suggestions I had read on this list, and consulting with a
> chemist friend, I now add about 5 ml of 5% HCl to 2 liters of rinse
> water to neutralize the buffering. (I could easily use other acids, but
> I had 1 gal of muriatic acid for some toning experiments.) I find that
> my wash water is now ALWAYS deep blue, but my images are also a deeper
> blue, and they don't fade away on me. I am slowly experimenting with
> reducing the amount of acid. Also, my solutions have been sitting on my
> shelf for a few weeks, so it is not the case of them being too "young".
As I recall, Mike Ware changed from Citric to Hydrochloric acid for his
New Cyanotype, since he had some suspicions (possibly since resolved)
about archivality after citric.
Judy
Received on Wed May 19 21:05:08 2004
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