Give me a page. Actually, this is one of the reasons why I find systems so problematic. The very nature of a system is to simplify the process in order to make it more manageable. Things will naturally tend to get lost in the process. On page 95 of the fourth edition, Davis discusses what he calls the effective DR. From page 95, "because you will want to produce negatives that print comfortably on your chosen paper, use the SI value you calculated in you paper test to locate IDmax (I hate his abbreviations), but do so only after making one further adjustment. This final adjustment is necessary because your curve data are based on a no-flare test condition, but you'll be applying the data to camera exposures that invariably involve significant amounts of flare."
Davis then applies a compensation to the effective paper LER instead of simply adjusting the LSLR, which is what actually happens. If someone skims past these two paragraphs on page 95 that explains how flare changes the aims, then their results will be off. Why not just have the equation NDR / (LSLR - Flare)? It's impossible to miss flare as a variable when it's part of the equation.
Did Fred say why? Don't accept unsupported statements.
Here's a four quadrant reproduction curve with a LSLR of 2.20, flare of 2.0, and CI of 0.56. The NDR and LER match.
Normal four quad.jpg
Last edited by Stephen Benskin; 02-11-2013 at 10:47 PM. Click to view previous post history.