POP/Platinum: Dense Negative or Just Contrastygreenspun.com : LUSENET : Large format photography : One Thread
I have heard that POP/Platinum papers work best with a dense negative (which I assume means a zone I density of more than .10). One stop more exposure than normal is a common suggestion.
I have experimented with negative density and contrast for POP paper using a step-wedge and real pictures. I found that extra exposure (beyond .10 for zone I) was not necessary or beneficial. I developed the negatives to high contrast, N+2 development for conventional paper. A normal exposure (.10 density for zone I) produced the expected separation of tone for zones II and III on the step-wedge and in the pictures. (Expected separation means good separation around zone III, and slight separation around zone II). Greater exposure did not change the rendition of the shadows in the prints, but it did block up the highlights, by placing zones VII and VIII too high on the shoulder (when developing for high contrast).
What I have settled on as normal for POP is standard N+2 development, with the film rated to give .10 density at zone I. This is 2/3rd stop LESS exposure than my normal EI for conventional paper, because the N+2 development pushes the EI up 2/3rds stop.
Do negatives for POP/Platinum really require a dense negative or just a high contrast negative? After testing this out, I think that the usual suggestion to give 1-stop more exposure when developing for alternative processes is bad advice.
-- William Marderness (firstname.lastname@example.org), August 31, 2000
For printing Platinum/Palladium you want a negative density range of approximately 1.4-1.6 for pure palladium you want to shoot for a NDR of approximately 1.9
Of course you need to tailor your negative to the scene and previsiualization. It is best to make your so that it prints the way you want without using any contrast agent. Contrast agents degrade image quality and create clumpy grain.
I shoot for a density of 2.45 in the brighest non-specular highlights and .5 in the deepest useable shadow areas.
-- Mike Kravit (email@example.com), August 31, 2000.
I use a 1.6 range for POP.
-- William Marderness (firstname.lastname@example.org), August 31, 2000.
I totally agree with you. I think that I don't need to overexpose to obtain good neg for POP Palladium platinum. I do most of my neg exposing the film at the good iso ( half the normal as I use ABC pyro developer) and I develop for N+1/2. this give me good rich negative which print easily without contrasting agent. when you use only palladium you can develop more. I also try to expose more but I just find it to block my black.
nze christian http://perso.club-internet.fr/cnze
-- nze christian (email@example.com), September 01, 2000.
More development than is normal for silver printing is essential, exposure is quite dependent on the film. With Kodak Tri-X sheet film and Ilford FP4-Plus a generous exposure helps shadow separation without hurting the ability to get a long overall scale. With films like HP5- Plus or Bergger BPF200--which have high levels of base fog and an early shoulder to the curve--extra exposure just cuts the available total range of tones and so should be avoided.---Carl
-- Carl Weese (firstname.lastname@example.org), September 01, 2000.
I had always heard "a greater density range" not greater density, thus the goal is higher contrast.
-- Charlie Strack (email@example.com), September 01, 2000.