There's a difference between film speed and EI or personal taste. Different interpretation of terms plays a major roll in much of the miscommunication on these threads.
Originally Posted by AndreasT
The ISO film speed standard incorporates a stop flare into the equation. The contrast parameters for development is to make the fixed density method correspond to the results from the fractional gradient method which bases speed on the shadow gradient. So gradient is a factor with ISO film speed. I'm not really sure what effect additional flare would have on the ratio between the fractional gradient point and the fixed density point of 0.10. Increased processing will reduce the ratio, which is why the fractional gradient method and Delta-X Criterion have effective film speeds that tend not to move with increased processing (a likely action with excessive flare).
Last edited by Stephen Benskin; 01-30-2013 at 12:16 PM. Click to view previous post history.