I am trying to evaluate Aristo ISO 125 8x10 film using the test procedures outli ned by Ansel Adams in _The Negative_.
I am measuring densities with a Highland transmission densitometer.
My developer is Ilford ID-11 stock diluted 1:3 with distilled water.
I am getting a reading of 0.03 for film base + fog
Based on what I understand from Adams' book, Zone 1 should be at a density readi ng of 0.13. I can get about this density with the film rated at ISO 100.
It is also my understanding that an increase in density reading of .3 correspond s to a doubling of the density and thus to a 1 zone increase in density.
If this were correct, then I would expect that Zone 8 should correspond to a den sity reading of 2.23. (7 * .3) + .13 = 2.23.
However, on page 242 of _The Negative_ Adams stated that he found a density of 1 .25 to 1.35 ideal for diffusion enlargers. By my reckoning, this density range is at bout Zone 5.
I am very obviously missing something critical here but I cannot figure out what it is. My step tablet that I bought from Phil Davis at Darkroom Innovations ha s 21 steps of .15 density increase each. The second step reads about .16. Goin g through the tablet you get .3 increase in density every second step. This mea ns that on this step tablet Zone 8 would be at step 16; taking the second step t o be zone 1. And step 16 on the tablet reads 2.26, very near to what I think Zo ne 8 ought to be but very different from what Adams states in the testing proced ures.
The matter is further complicated by the fact that I cannot seem to get the dens ity of Aristo 125 (rated at 100 and exposed for Zone 8) up beyond 1.95 regardles s of development time.
I thought someone out there might have some insight into what I am doing wrong h ere.
Thanks for any information you can provide.