From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 01/28/02-07:18:50 AM Z
clay wrote:
> After Carl's comments about using LiPd in DOP, I ran a quick step
> wedge
> comparison test yesterday of the different metal salts and their
> response at
> the beginning of my printing session. ... I've plotted the results
> of the test on
> a excel spreadsheet for anyone bored or curious. ....
> The bottom line is that the LiPd seems to have a
> slightly
> different speed and have a more linear response than NaPd.
> There also is a very
> slight color difference that is harder to see on the step wedge
> than on an actual print.
It would be interesting to see all the results. You may privately
E-mail me the spread sheet as an attachment.
I would recommend to be very cautious of these conclusions. Ambient
Temperature and Relative Humidity, and the paper used can impact these
results greatly. For example, DOP with LiPd on Bienfang 360 paper at
65F and 35% RH can produce a very warm orangish brown color (not
necessarily cooler than the other salts and warmer than NaPd).
I have found the color differences to be quite distinguishable. There
are some speed differences, but speed is also influenced by many other
things.
I am not sure what you mean by a "more linear response", as any of the
metal salts can provide a very straight response and provide remarkable
tones and tonal discrimination throughout the total dynamic range (white
to black). It is very important that each metal salt be optimized in
solution strength to match the appropriate strength sensitizer. If
"weak" prints are produced (not enough metal), these results can easily
be skewed. Also coating technique must be perfected or results could be
easily skewed. Even a most experienced printer must coat carefully and
accurately for a fair comparison.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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