The curve seems a little odd to me. For one thing, it should not flatten out so abruptly that early (~7 stops above metered).
I'm not 100% clear on the exposure methodology but here are a few tips.
I would suggest keeping the exposure time for the entire series <1s to avoid reciprocity problems. Also, with a brightly lit sheet of paper, unless you are carefully masking the lens/camera there can be a significant camera flare factor. Aside from that, if you are covering half the frame, flare can have a significant influence on the density in the darker area. In general, flare would tend show up as increased film speed and reduced shadow contrast on the characteristic curve.
If you are shooting a brightly lit test target I'd suggest masking the lens to reduce camera flare. If done effectively you'd be basically left with some veiling lens flare. To avoid flare altogether you'd have to contact a step tablet/wedge.
Hope this helps.
Good start. But can you explain the methodology a little more? Why was each frame exposed twice? Were you exposing film in the enlarger at the film stage? Etc.
Last edited by Michael R 1974; 12-30-2012 at 03:07 PM. Click to view previous post history.