From: Sandy King (sanking@clemson.edu)
Date: 09/29/02-03:46:11 PM Z
Richard Knoppow wrote:
>Plus-X and Tri-X sheet film are very long
>toe. In fact, they are nearly all toe since neither film has
>an appreciable straight line section. Plus-X pan sheet film
>is somewhat more exagerated in this respect than Tri-X pan.
>Both films have D/logE curves which are inflected upward
>everywhere, meaning the contrast increases continuously with
>density.
> Neither film is "high fog" and neither shoulders off any
>any useful density, even the rather high ones sometimes
>desired for Platinum printing. Dr. Richard Henry found that
>Plus-X sheet film had an exposure latitude of twelve stops
>overexposure. Such a dense negative would be extremely hard
>to print but would still have fairly high highlight
>contrast.
> Since the self masking effect of Platinum tends to flatten
>out the shadows, and since long toe films do the same, a
>short toe film like T-Max would probably yield more
>satisfactory results.
>
I have some doubts that the self masking effect of platinum is strong
enough to have any significant impact on the shadows. Nevertheless I
agree with your supposition that a straight line film like T-Max
might give more satisfactory results, i.e. more vigorous shadows, in
platinum than a film like TRI-X. For whatever reason a platinum print
has a fairly long toe, which when combined with the long toe of TRI-X
film, may be the reason so many platinum prints don't have much punch
in the shadows. On the other hand, a film like TRI-X, which does not
shoulder, works great in the highlights in platinum, since it tends
to counter the rather significant shouldering of the platinum
process, which increases even more as you add more and more palladium
to the mix.
Sandy King
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