In a message dated 3/5/06 8:29:50 am, gauvreau-yves@sympatico.ca writes:
> But if I was satisfied with a relatively low Dmax, say the 1.2 as
> Sandy said earlier and the relatively flat response obtainable from a single coat gum
> print. I would approach the problem this way, first I would make enough gum
> emultion such that can make quite a few test and prints without changing
> anything to my recipe. One of my first test would be to find how much exposure I
> need to secure the target Dmax. The next test would be to print a standard
> step tablet to learn the response of this particular emultion/paper combo if
> not already done simultaniously in the exposure test. Now I don't presuppose a
> linear response would suit the image just like that and I would use a
> negative feedback approach to find what kind of curve I will use for this image on
> this particular emultion. The way this would be done is say I print a
> negative where the densities progress in a strait line from min to max and to compare
> it with a different version, I could begin by increasing the contrast in the
> highlights, if I don't like that I could try the same with the shadow and so
> on until I'm satisfied I've made the finest print I could.
>
Yves
That is not how gum works.
Gum has a limited density rande. The maximum for ideal gradation is probably
about half of what Sandy suggests. One overcomes this by overlapping multiple
exposures. I do so as I control the colour this way. An alternative for
monochrome printing could be to use a very fine grain pigment which may result
in an appearance of good gradation and range. That is what I am about to check
in the articles in La Revue de Photographie. Another good source would be
Photograms of the Year.Both have articles by the likes of Steichen, Puyo and
Demarchy.
I remain unconvinced that the use of digital negatives has anything to do
with it. After all, Puyo was making these monochrome single exposure prints in
1900 !
Terry
Received on 05/03/06-03:50:48 AM Z
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