high base fog

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.

This may be over development.

Try a fresh roll of HP5 and fresh developer. Heat and other factors may have fogged your film.

4x5 films tend to be manufactured on "clear" base, while 35mm films may have a "base tint" for antihalation purposes.

rmolson, have you ruled out what you see isn't just normal base tint?

IF .30 is normal base density for HP5 then my reading make sense. Just use to much lower base density from sheet and roll film. Will need to adjust development times though.