Greetings!

I am trying to learn how to develop and print all over again. My first step was to try to figure out my film speed. I'm using T-Max 400 in 4x5 sheets, developing in D-76 undiluted in a Unicolor drum that I rotate by hand. I am using T-Max because its reciprocity failure characteristics are much more merciful than Tri-X, and since I like depth of field, I am often shooting at f32 or f45.

For my first test, I found a smooth, dark surface, metered it, and underexposed it by 3, 4, 5 and 6 stops, pulling the slides out half-way. I figured that the first negative I saw the difference between the exposed and unexposed halves of the slide would give me a Zone I exposure and an approximation of film speed. This gave me an indication that 400 is a reasonable speed for this film, but I don't know whether I am really above the foot of the light curve for the film.

I tried printing that negative to get an idea of what the standard print exposure would be. I use an Omega D-2 condenser enlarger with a 135-mm El-Nikkor lens. A stepped-exposure print showed me the first difference between the exposed and unexposed portions of the negative at 24 seconds at f45. That seems very fast to me. I found a nice, contrasty subject to test this with yesterday. The film has been developed but I haven't had a chance to print it yet.

I saw a post here in which somebody mentioned using a home-made densitometer to check that his Zone I exposure was giving him a density of 0.11 above film base and fog. I strongly suspect that I don't have that much density. So, is there a way for someone with a simple darkroom setup to find out what Zone I should be? Or should I figure on spending a couple hundred dollars for a used densitometer on E-Bay?

Thanks very much!

Rob