From: Judy Seigel (jseigel@panix.com)
Date: 02/02/03-01:28:21 AM Z
On Fri, 31 Jan 2003, Sandy King wrote:
> The confusion and/or inaccuracies that exist in the literature may
> result from the fact that in addition to processes that are POP and
> those that are DOP, there are also processes that are POP to varying
> degrees. In another response to your message Richard Knoppow notes
> that there are two mechanisms for self masking: the increasing
> density of the photolytic silver holding back
> further light, and desensitization with increasing exposure.
that's reciprocity failure, which can happen to anybody, any process, and
irrelevant to this discussion.
> With most forms of kallitype, as well as platinum and palladium,
> exposure forms only a whisper of an image, much too faint to cause
> much self-masking. The same would appear to be true of cyanotype.
Sandy that is absolutely not true. I knew it wasn't true & you have cost
me 20 minutes of my remaining time on earth to again prove that it wasn't
true. That is, a cyanotype exposed but not developed showed density in
the darkest shadows equal to number 9 out of a possible 19 on the Kodak
Gray scale. I consider that substantial, not "too faint to cause much self
masking."
I personally don't give a fig about self masking, or why it matters,
since each medium combo has to be tried separately... but what I do give a
fig about is "Truth in non-silver," something I've noticed the books play
fast & loose with & then copy more nonsense from each other.
The other thing that's baloney (I wonder did they ever actually TEST or
just THEORIZE!!) is the business about the blue color passing light
through because -- what -- not actinic sensitive? I forget the jargon.
Whatever, I stuck in 2 little pieces of light blue gel, separately and
overlapped -- and guess what -- yeah, definitely lighter in those areas.
As noted, this took all of 20 minutes & I'm not even writing a book.
However, I doubt there's much self masking in cyano because that full blue
takes a while to print out, and my test was for the whole exposure time of
10 minutes. I'm not disputing the conclusion (if it matters), I'm simply
pointing out that false assumptions are .... false but if repeated and
repeated become "fact."
Incidentally, the paper I use for everything anything like this is some
very old Strathmore drawing, rag, thin, hard finish -- with two coats it's
so dark blue it's almost black...
Also, BTW, item in the Times that they're going to use Prussian blue to
fight effects of a dirty bomb. All else failing we can eat our cyanos.
Judy
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