PT/PD Negative Density Range.greenspun.com : LUSENET : Large format photography : One Thread
I have seen in other posts that a 1.8-2.0 negative density range is best for pt/pd printing. I don't understand exactly what this means. If I were to use a 1.8 density range as the target, would I place zone I on .10 and zone VIII on 1.9? Does a 1.8 denstiy range refer to the difference between the density of zone VIII and zone I?
-- William Marderness (firstname.lastname@example.org), February 18, 2002
I can't answer about density range as I never messured any of my negs. I use to proof on a grade 0 or grade one paper to determine what mixture of PT/PD solutions to use. Don't forget PT/PD can be printed in different contrast grades.
Also the paper selection effects contrast, tempature of the chemicals, ....... there are many more things that can change the print contrast in PT/PD printing.
I will say that I always liked to print with "meaty" negatives rather then thin ones. It is much easier to control the print exposure. But don't take that as meaning bullet proof negs either.
-- George Losse (email@example.com), February 18, 2002.
it is my understanding in using a densitometer to measure negs for plat/plad printing, that the shadow density for plat/plad and silver, should be about the same, approximately 0.3. the highlight density should be approximately 1.7. please see chapter 3 of dick arentz's book, "platinum and palladium printing".
-- howard b. schwartz (firstname.lastname@example.org), February 18, 2002.
William , The density range is the difference between where you want detail in your shadows and detail in highlights. When you extend development to get more contrast you will probably need to give less exposure to your film because you will raise the lower densities and get too dense a negative. I find rating the film higher as easy way to take care of this. Hope this helps William
-- William Blunt (email@example.com), February 18, 2002.
William; What little I know aout Pd/Pt is that the highlight densities in a neg may be greater then for silver paper because Pd/Pt papers have more range for highlights. That means the dynamic range is indeed a stop or two greater than with most silver emulsions, and as mentioned above, much depends on the mix of chemicals as well as temperature, hunidity, phase of the moon etc.
Arentz' book as well as info from Bostick % sullivan and Palladio will help. The book "Keepers of the Light" self-published by Louis Nadeau is most helpful.
I had great success with T Max 100 rated at 50 and 400 rated at 200, then drevelpoed insplit D-23 Sol'n A 3 Min, Sol'n B, 10 Min. This gives a neg that prints on Grade ) paper and beautifully on most Pd/Pt formulations.
-- RICHRRD ILOMAKI (firstname.lastname@example.org), February 19, 2002.
Short answer: The difference is all in the developing stage and it has nothing as such to do with the zone system. (Even though you still use the zone system to decide the developing time.)
More elaborate: Let's start with "normal" printing first. When you shoot your picture, you decide for N- .. N+ etc. As you've already calibrated your developing procedure, you know the developing times for N, N-, N+ ... This will give you a negative that has a density range around 1.0 (depending upon your enlarger light source, if you are enlarging.)
When you shoot an original for PT/PD you behave in the same manner as when shooting an original for silver-based printing. The difference is that you have to calibrate your developing time for a neg. density range of 1.8-2.0 instead of around 1.0. This is because the PT/PD emulsion is much softer than a normal grade silverbased paper.
You possibly have to use an intermediate negative instead of the original. I.e. an orthochromatic darkroom film, which you can develop to higher contrast. This gives you the opportunity to burn in/shade off etc. on the negative that you will use when exposing the PT/PD. And, not all normal films are good for developing to a density range of 2.0.
-- Björn Nilsson (email@example.com), February 19, 2002.
Richard - The 3 min in A (elon and sulfite) and 10 min in B (Kodalk) for divided D-23 development sounds reversed. Is that a possibility?
-- Joe Lipka (firstname.lastname@example.org), February 19, 2002.