From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 06/15/01-08:03:10 AM Z
Sandy King wrote:
> ... The self-masking aspect of
> the POP and Salted paper have the obvious effect of reducing overall
> contrast as exposure times increase.
Yes, it seems that the print-out (self-masking) would do this. But this
is only my speculation. Has anyone studied this to really know what is
happening and how to control it?
shannon stoney wrote:
> What is this self-masking thing you speak of?
When a Pt/Pd coating is exposed, the material is partially developed
(full development with a POP). This partially developed image is known
as print-out or self-masking. With familiar materials and procedures
the print-out can be used to evaluate a print and determine if more
exposure should be given.
The self-masking is when an area prints out, the printed out portion
blocks the light from further exposure of that area. Since the print-out
blocks more in the shadows than the highlights, the highlights will
effectively receive more exposure. This then serves to effectively
reduce the contrast (if dark values are set, the upper values are
reduced).
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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