Ooops it wasn't Sandy -- sorry (too much standing over a hot stove
stirring) -- it was Mark. But I still don't get it.
On Mon, 24 Nov 2003 Ender100@aol.com wrote:
> Judy,
>
> In response to your response to Sandy's response to.... regarding your doubts
> whether Pictorico might be a tad slower than other film.
>
> With PT/PD, I've done test strips with clear Pictorico film and a Stouffer's
> step tablet. Sam Wang suggested this as a method of determining base
> exposure when printing using digital negatives on any film substrate substrate. It
> works very well, and I have done it many times with different combinations of
> PT/PD, Na2, various papers, and even tried it on my undershorts. It's the
> best method I have found for determining your base exposure time. If anyone
> can see folly where I tread, please enlighten me.
Again, in gum my base exposure time is entirely generic... and I often
decide during development how far to go. but still... I would be happy to
understand this technique, which at present i do not...
> I took the Stouffer step tablet and laid it over the edge of a piece of clear
> Pictorico film in such a manner that the edge of the strip of Pictorico
> bisected the Stouffer step tablet. I then made an exposure of roughly 2-3 times
> what I thought was was my ballpark exposure for this mix of PT/PD on the given
> paper with a NUARC—to make sure I would end up with at least two steps
> merging. Once developed and dried, I examined the test print with my own eyeballs
> and looked for the point where two dark steps of the printed Stouffer merged.
> I found it. I celebrated. I even double checked with a desnitometer
> appropriately set to reflective mode. The merging of the two steps was exactly
> one step lower for the portion that was also covered by Pictorico—in every case.
> I should add here, of course, that this was the infamous Stouffer #T2115 21
> Step Sensitivity Guide (granted, the uncalibrated version, which costs more),
it does? You're putting us on...
> which measures exactly .15 log transmissive density per step give or take a
> lumen or two.
>
> At least for PT/PD and God only knows what other alt process, I would have to
> say that I am convinced beyond a shadow of a doubt and I would even bet the
> life of my first-born....well maybe my second-born.... that clear Pictorico
> film measures about 1/2 stop or .15 UV density. When I measure it with a
> transmissive densitometer, I get exactly log .04 transmissive density, from both
> sides (just in case the ceramic coating caused some weird, unidirectional
> abberition), which is a fair amount less than .15 log density.
>
> Now perhaps I should qualify all the above with a disclaimor that the UV
> density suggested by this series of observations would apply to that spectrum of
> UV light that caused my PT/PD to do its trick. I won't go into my undershorts
> at this writing—for that contact me off list.
>
> What Sandy is referring to is clear Pictorico film, not Pictorico film or any
> other film that has silver or ink or fingerprints or dust or chicken soup
> smeared, sprayed or gicleed on it. This is an important point to remember when
> using Pictorico—it is a great substrate, but it does add overall density to
> your negative.
>
> Now if we are going to talk about how inks block UV light, that's a whole
> other discussion, but not the one that Sandy is referring to.
>
> Kindly submitted to this august group by your humble servant this Year of Our
> Lord, 2003. ;)
Well, on 3rd thought, maybe this is not a subject to pursue... :- (
J.
Received on Thu Nov 27 00:14:08 2003
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