Funny enough, I was planning on doing something very similar, so I sincerely hope that you don't lose your interest in this project or let others discourage you!
I have some related questions, too:
- Is it really possible/feasible to 'translate' the zone system into an 11-step scale from 0 to 255, defining zone V as 128 (or 127)?
- Assuming I have the stuff printed on matte paper, and I would take not to put the test target into bright sunlight, would this mitigate the issue of reflectivity?
- What about subject and print luminance range? Is it by principle not possible to print 10+ zones, even digitally, in a way to capture them as 10+ zones on a negative?
- and while being at it, would it make sense to consider any 12%/18% gray issues for metering etc.?
There are a lot of issues to consider. Basically, most of the testing is to find an EI and not the film speed. As such, you really don't need to be precise, but to do any kind of proper testing, you need to understand what you are testing for and the variables and conditions involved. A beginner creating thier own testing procedures really isn't the most practical approach. You're attempting to reinvent the wheel without understanding what it is.
Originally Posted by sewarion
Ten subject Zones equals ten stops or a log luminance range of 3.0. Glossy paper has around a maximum of log 2.0 relectance range. Matte paper has less. If you want to use your own scales, have them measured and use those measurements to compare with the finished print. Personally, I would recommend testing the film using a step tablet, and don't get caught up thinking only in Zones.
Microtonality mid-scale is a distinct (though related) topic to overall range of the film. It will differ with
different films, different development regimens, differernt print papers and developers, and even different camera lenses. To make sense of it you'd first need to learn to plot these step readings onto a curve using a desitometer, assuming you understand how to interpret these things in the first place. The Zone system is only moderately useful in this respect. It's pretty generalized. Eventually you just have to home in on a specific film, developer, and paper to learn the working dialect. Othewise, buy a
serious textbook on sensitometry - which will itself have little practical value unless you understand
what you want your film to do !