A version of the Kodak diagram can be found in Way Beyond Monochrome. It can be found online: http://www.waybeyondmonochrome.com/W...ductionEd2.pdf
WBM Tone Reproduction Diagram.jpg
At first glance it appears to contain the same data as the Kodak diagram but with a Zone System emphasis. They both have a Subject line, an Optical Image line, a Negative line, and a Print line. Both have a 7 stop scene luminance range for the subject. Way Beyond Monochrome’s negative is developed to CI 0.57 which is almost identical to Kodak’s CI 0.56.
With all due respect, where they differ is with the resulting negative density range. Way Beyond Monochrome has a NDR of 1.20 for a 7 stop scene with the film processed to CI 0.57. Kodak has a NDR of 1.05 for a 7 stop scene with the film processed to CI 0.56. How is it possible to have different resulting negative density ranges from almost identical conditions?
While the Way Beyond Monochrome diagram shows the effects from flare in the Optical Image, just like the Kodak diagram, it doesn’t factor it into the equation for the resulting negative. This is confirmed in another part of the book, Testing Film Speed and Development, http://www.waybeyondmonochrome.com/W...Evaluation.pdf.
“In addition, we also sets the normal log exposure range to 2.10, since we need 7 subject brightness zones to expose the 7 paper zones above, and each zone is equivalent to 0.3 log exposure. The normal average gradient can be calculated as 1.20 / 2.10 = 0.57. “
The desired negative density range is divided here by the scene luminance range, and not the camera exposure range. Both the Way Beyond Monochrome diagram and the Kodak diagram show the existence of flare in their models. It’s impossible to get different negative density values from the same set of conditions. In order to acquire a desired negative density of 1.20 under the conditions displayed, for the Way Beyond Monochrome negative needs to be developed to a CI of 0.67.
1.20 / (2.1 – 0.30) = 0.67
Last edited by Stephen Benskin; 01-22-2012 at 07:57 AM. Click to view previous post history.