Re: FW: UV blocker in TMAX100 base?

Date: 02/25/04-09:23:17 PM Z
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This was what I didn't understand...

Judy: "Oh my, the material I tested was at most maybe 2 steps lighter...or
2 minutes out of 8 minutes... Having found a surprising difference
between guide (among guides???), & not knowing in advance what the
difference will be, I would use the same one, at least for starters."

It sounded as if the material was cutting the exposure by two steps or a full
stop. If so, and if your standard exposure time was 8 minutes, then you
would have to double the 8 minutes to compensate for the material's full stop
density—or are you saying that the material cut the exposure 2 steps (a full stop
on Stouffer) and that was the equivalent of cutting the exposure, which in
that case it would be the same as halving the exposure of 8 minutes to 4
minutes, not 2 minutes. Or how bout this—let's get a couple bottles of wine, some
cheese and cracker, look at the two cyanotype prints of the Stouffers, and wait
an hour and maybe we won't even give a damn! hehehehehe

Mark Nelson

In a message dated 2/25/04 4:10:20 PM, writes:

> On Wed, 25 Feb 2004 wrote:
> > Two steps difference on a Stouffer 21 is .30 log density., which means by
> > using the substrate you are talking about you would need to double the
> standard
> > printing time to compensate for it.   I'm not sure what you mean by 2 mi
> nutes
> > out of 8 minutes,,,,
> Good grief Mark, if you don't know, how am I supposed to know...?  But
> that was actually a bad choice of words late at night, from memory. So I
> have  gone back to the test strips (found them !  tah dah !!!) and note
> the following:
> Both were cyanotype exposed 8 minutes, but done several days apart and NOT
> with the same strip.
> The one under a piece of plastic from a stack bought as "antistatic" (very
> clear & fairly lightweight) shows a just barely detectable difference on
> step 1, but a very distinct difference at step 8, though still some tone.
> The not-covered side has very slight "veiling" at step 9, but not a real
> step. So maybe that would be "one step" less... but 7 of the steps are
> lighter.
> The one under Saran wrap also shows 8 steps, but step #1 is the same, step
> #2 is nearly the same, that is you wouldn't notice a difference if you
> weren't looking for it, difference detectable on step #3, more noticeable
> on 4, 5, 6 & 7, both #8s are pretty pale and probably no #9 at all.
> That's what I mean about using the same strip -- I don't know if the
> difference at the very light top end is from difference in the strips or
> my handling, or the masking material.
> In any event, I don't know how you'd designate it -- be my guest.
> However it did occur to me that if the difference under the Saran wrap
> holds for other emulsions... it could be a handy way of increasing
> contrast without additives or intensifying the neg. Since D-max is
> virtually the same, you ought to be able to fill in the mid and high tones
> without by adding exposure -- without flattening the image.
> J.
Received on Wed Feb 25 21:23:40 2004

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