Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Thu, 18 Feb 1999 16:25:55 -0500
Dan Koons wrote:
> ...
> Isnt zone ten white paper? Is there just more shades of gray between max black
> and lightest shades of near white when dealing with pl/pt. ...
No, not really, and certainly not when palladium is involved. Palladium
just wants to show the faintest exposures. I had once thought that zone
X was supposed to be the limit of pure paper white. But just as zone 0
is not pure maximum black, zone X is not pure maximum white. A limit of
zone X may be the assumption for gelatin silver. However it seems that
there is a very non linear response in that Pt/Pd, and especially Pd,
are more sensitive to slight exposures. I have palladium prints which
discriminate zones X, XI and XII.
I suspect that this effect is not just the self masking which Pt/Pd is
known for. In 100% Pd prints, I have found densities from highlights,
specular reflections, filaments in light bulbs, and the like. These
values are at X or above, but still print a discernible tone. Remember
that when dealing with high values, the adjacent values will have a
great impact on their interpretation. A high value next to another high
value is much more apparent that if next to a dark value.
This sensitivity may also be why I am very cautious about using a
sfelight (sodium vapor works well) for the Pt/Pd process. I have found
incandescent light to fog the print (and the yellow bug lights too).
(There is a procedure for testing fogging in my guide.)
Being that I have retired from working as a physicist, I don't get into
doing experimental research on why these things work. I only research
what can give me the look I want in the print.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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