On the issue of contrast, my remarks are primarily regarding the
printing-out processes I use these days (Albumen, Salt, P.O.P.), since I
haven't yet tried the same neg. for Pt/Pd in both sun and a light bank.
(Does the slight printing out of Pt/Pd make any difference?). I suppose
VDB would also fall under this category...
I once inferred (incorrectly) from Friedlander's discussion of making
the E.J. Belloc prints, that softer light and longer exposures gave more
contrast. The _opposite_ is true. Here's why:
Quick exposures under strong light cause a darkening of silver nitrate
emulsions faster than the natural self-masking effect can act. In soft
light and a long exposure, the dark areas of the print _slowly_ darken
and at the same time inhibit further exposure as they print out, leaving
more details visible in the shadows (less contrast). [There is also a
color difference as the silver animalculae, oops, I mean, silver
clusters are larger or smaller in proportion to the intensity of light.]
So, "strong" light can be the sun (vs. light bank), or blue glass (vs.
reg.)... I think. For super contrast try both...
Now, does this apply for non-silver processes, such as gum? Let's get
the scientists in on this one - anyone?