Am doing film testing trying to get myself on track. with FP4 , rodinal, forte polygrade V and dektol 2:1. My speed tests indicate 100 asa is good but am having a hell of a time getting a zone 8 developement time. I expose a full sheet to Zone 8 using a diffusion glass pointed at the sky(much like Ansel Adams pre-exposure recommendations) metering directly in front of the lens then setting my exposure for zone 8. I just developed my last 2 shots; one at 25:1 for 7 min and one at 50:1 for 11 minutes...................they both came out almost exactly the same around 1.6 measured on my densitometer. I don't use the densitometer to calibrate just as a measuring device to see where I am. I know I need a a density of around 1.25 to get zone8. any thoughts as to what I could be doing wrong? I did develope just one film at a time in a tray carefully measured the temp at 68deg one with 20ml per 500ml and one with 10ml per 500 ml. Is it that I have developed them singly? I ususally develope4 at a time ala slosher.