FotoDave@aol.com
Date: 09/30/02-01:32:04 PM Z
Print-out Pt/Pd (Ware/Malde, Ziatype, original Pizighelli) has enormous
self masking with a clear drop in contrast as exposures are extended.
Low values almost completely "stall" while highlights keep getting
darker.
Carl,
But technically speaking, the above simply says that it is a long-shoulder
process. As I also mentioned in my previous email, the long-shoulder itself
might be caused by self masking, but it might be something else.
But going back to the original question about H&D curve shifting, if we do
have accurate enough densitometer that measure small enough change in density
(and assuming our process, coating, exposure, etc. are fairly reapeatible),
when we increase or decrease the exposure, the curve simply moves left or
right, self-masking or not.
The apparent decrease in contrast is because, as you said, the density change
in shadow is little but the density change in highlight is more. That in
itself doesn't say that the process is self masking.
Dave S
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