Quote Originally Posted by noseoil
Jim made an interesting comment about the placement of zone 1 at 0.1 above film base plus fog in the "Victoms of the Zone System" thread by Chuck1. While I know this is the conventional wisdom with respect to the location of zone 1 (BTZS and ZS), I have had a similar finding to his. For the actual use of film, he states that zone III should be placed at closer to 0.4 above FB+ fog for any real use of shadow values.

I'd been trying to balance film with azo paper, on and off for a year and a half, and am finally having some success. One large problem has been the selection of film speed. I'd been beating my head against the rock, trying to figure out how claims for full film speeds and full shadow values could be made. After doing film tests which were useless for actual print making, I have come to the conclusion that tests should be done to give exposure which is far above the "normal" amount of light if shadow detail is to be of any real use in a print on azo.

I suspect my stubborn use of Efke 25 for azo has been a large part of my self-imposed frustration. I have finally settled on asa 6 as my "normal" film speed for grade 2 azo. Fortunately, Efke 25 is very long on contrast (up to 3.0 with some developers). If you look at the data on J&C's site, you can see a toe which goes well up towards 1.0 before it gets to the straight line portion of the film. Since I don't have a densitometer, I don't have actual numbers to go by. This finding for shadow values has been verified by in a similar manner (step wedge testing, FP4+) with different films and has shown a departure from the conventional wisdom as well.

I'm wondering if this is peculiar to azo and tests, or if others under rate film this much as a rule? What about alternative process, are there similar findings about exposure and shadow values? Thanks, tim
Couple of things, while you can calculate film speed by the .1 method with the BTZS, it is usually done by CI which IMO is more reliable.
Now, your apropriate film speed is also determined by the paper you use. For example, in my film speed and developing test using the BTZS with Pyrocat HD and TMY as well as Ultrafine (knock off Ilford) I got full film speed but since pt/ pd compresses the tonality so much when printing, I cut the speed in half, effectively moving all the values up on the curve one stop. So for me, "zone III" is actually 0.6 to 0.7 as opposed to the "Adams" values of .3 to .4.
Azo has a very good DR, in fact far better than pt/pd but from what I understand MAS develops his negatives to be very dense, which leads me to believe Azo might be in the same boat as pt/pd, since it has such a long range, perhaps using higher density values for the shadows might be a good thing.
IMO the object of testing, either by the ZS or the BTZS is not to obtain the thinnest possible negative with all the information, but to obtain information that will allow you consistently produce negatives with the desired information in them. With roll film it is important to get the thinniest possible negative to reduce grain, we dont have that constraint with LF.