From: Yu rei (nanocrystals2003@yahoo.co.jp)
Date: 05/24/03-06:00:46 AM Z
--- Halvor <halvorb@mac.com>：
Hi Halvor,
I have not worked with pt/pd nor have I worked with
densitometers for several years now but when you think
about it, since the coatings are subject to natural
variations for various reasons, (as jeffery briefly
touched on and you yourself are surely aware of) wouldn
’t you expect to see the greatest variation in the mid
tones as the is curve is rising here quite rapidly; the
other areas simply being less sensitive. I checked my old
data where I had done multiple coating tests of
“Liquid Light” and “Em16a” and the variation I got was
more on the order of 0.01 when variations occured, but the
values were significantly greater for the straight line
area than either the toe or the shoulder. I found a few
instances of a variation of 0.31 and even one instance of
a 0.89 difference between coatings (Liquid Light). (Mind
you, this was in coatings where a change was sought after
as I was testing the effect of multiple wet coatings- your
0.1 to 0.2 values might seem high but they do fall within
my results for AgX under certain circumstances.
As Jeffery alluded, are these differences visable to the
unaided eye?
Just out of curiosity, Were these coatings done at the
same time? How consistent is you measuring? Are you making
multiple readings and avereging? (I think I took 3
readings and used the average.)
Are you using the "Visual" (orange?) setting?
Also, is your step wedge in 1/2 stops or 1/3 stops?
Just curious!
Someone else on the list with extensive experience in
Pt/Pd should comment on the sensitomitry of platinium
printing. I am just walking in space.
Ray Rogers
Personal to Halvor:
By the way,
I saw you in class the other day (4th floor, near the
door...)and you looked better than when we first met. Your
hair has grown out a bit and you had a very relaxed (laid
back?) look on your face! I would have stayed to talk but
you were in the middle of class.
Maybe next time!
Good luck!
Ray...
> Hi group
>
> what would be a "normal" level of fluctuation in the
> curves when testing
> palladium ?
>
> I have done some tests but find it hard to pin down
> the results. The curves
> tends to vary up to 0.1 to 0.2 Lg H in the midtones,
> (toe area & sensitivity
> point tend to be reasonably similar, D max stable
> but position varies),
> basically the contrast is unstable. Is this just a
> result of uneven coating
> or other factors, my measuring, or simply is
> palladium printing this
> "unstable" ?
>
>
> Halvor Bj・瘢雹ng・瘢雹d
>
>
> FeIII from B&S
> cranes platinum paper
> "basic/traditional formula"
> problem seems indipendent of light source, sun,
> mercury halide, HID, studio
> daylight bulb.
> coating with rod, dryed with hair dryer, exsposed
> dry,,,,,
> coating area similar
>
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