Base density level Getting back into photography after a two year absence. I have been getting overly heavy negatives on my 35mm work So I ran a whole zone test Using HP5 rated at 250 in Claytons F-76 1:9 I got a base fog of .28!!! Which put my zone I at .50 .28 =.22. Obviously why off. I checked on both of my densitometers and they agreed. The calibration strip was spot on,.I use to do this for a living. The House is not air conditioned and the temperature got up in the 80s this summer How resistant to heat fog is HP 5? Claytons F-76 is suppose to be similar to D-76 and I never got base fog this high with D76 on Tri X.