[alt-photo] Re: Multi-Neg Printing Methods

[etienne garbaux]

Francesco wrote:

>My primary concern is exactly what you
>describe in your response on exposure. I understand that the "shadow neg"
>will be blocked up in the mids and highlights effectively producing little
>exposure in the midtones and highlights in the print. Likewise, the
>highlights values will be blocked up in the "midtone neg" preventing most
>exposure to the highlight areas of the print. My concern is that the areas
>in the "midtone neg" and the "highlight neg" of lesser density will cause an
>overprinting over what has already been printed in the lower print tones by
>the previous negative printings. Is this just a non-issue for some reason
>that I'm not seeing or is any increase in density in the mid and lower print
>tones simply something that needs to be worked out and compensated for
>through test strips? I'm just not seeing how the mid and low print values
>can be maintained after the "midtone neg" and "highlight neg" are printed.

I have only very limited personal experience in using multiple 
negatives this way, and that was long, long ago in a darkroom far, 
far away.  I know others who painted the shadow areas of their mid 
and highlight negatives with masking shellac to solve this problem, 
but that was a bit too manual for me.  As I said before, I quickly 
took up using the Dye Transfer process to make Pt negatives, and more 
recently I have used straight-line films, overexposure, and hearty 
development to make in-camera negatives with a DR in the 2.5 to 2.7 
range and a Dmax near 3.0 (i.e., no image areas less than 0.2 to 0.25 
density, so all of the shadow areas are well off the toe).  I now 
actually like Pt prints better this way than with artificially 
fortified shadow tones.  There is enough shadow contrast (way more 
than most contemporary Pt images I see), but not so much that the 
prints look "tarted up" with artificial shadow tones.

The fact that Salto is reported to use sandwiched "negatives" for the 
midtone and highlight exposures suggests that one of each pair is 
actually a positive mask used to control the shadow exposures through 
these negatives.

In the bad old days, we used a generally similar method to control 
contrast, using Kodak Commercial and Professional Copy films (moment 
of silence for the loss of two of the most useful sensitized 
materials ever made).  There is lots of old literature on "contrast 
masking" (not to be confused with the relatively recent practice of 
"unsharp masking"), some of which would likely be relevant to your quest.

Now:  Since Salto is using imagesetter negatives, I'm not sure I see 
the need to actually create film negatives and masking positives -- 
one should be able to design curves in the digital domain for the 
highlight and midtone negatives that accomplish the masking directly 
on the negatives.  But then, I have no familiarity with his process 
and all of what I have said about it is purely speculative (though 
seemingly plausible, IMO).

Best regards,

etienne