Quote Originally Posted by AndreasT View Post
May I go back to the Delta X Criteion paper. Being confused as ever, reading and re-reading. (Having a headache)
I have now various curve for various films. To use the DeltaX I take the curve where the ISO triangle matches most closely and basically subtract the Delta X value. Being 0.296
Next I take the rest of the curve measure using the same ISO triangle length 1.30 log-H but with the higher Delta which touches the curve to find my Delta X Criterion from the table.
This will then show all speed point for the different curve.
The various ΔX values are based on the value of ΔD. There's a table with the values. Say you have a ΔD of 0.86, the ΔX value is then 0.268. The fractional gradient point is 0.268 log-H units to the left of the fixed density of 0.10 over Fb+f. Take the log-H at that point and plug it into the equation 0.4 / Hfg.