View Full Version : FP4 Reciprocity

Chris Strobel
4-Apr-2007, 08:20
Hi, am I correct in assuming the reciprocity corrections are the same for FP4 and HP5?


Scott Kathe
4-Apr-2007, 09:07

I just took a look at the Fact Sheets from Ilford for FP4+ and HP5+ and the exposure compensation curves look the same to me. I've only used FP4+ and the curve has worked fine for me but I'm a novice.


Ron Marshall
4-Apr-2007, 09:09
Yes, they are the same.

Chris Strobel
4-Apr-2007, 09:13
Yes, they are the same.

Thats what I thought.Just wanted to double check.Thanks guys!

John Powers
6-Apr-2007, 04:23
Pack a lunch. They are long.


Bruce Osgood
6-Apr-2007, 09:22
I've had occasion to use the 4+ long exposure compensation factor supplied by Ilford and yes, they are long, and they are exact in my findings.

Chris Strobel
6-Apr-2007, 09:42
While this thread is still sorta alive, in Steve Simmons book, He has a table of reciprocity corrections and development reduction suggestions.So lets say your corrected exposure time is 24 sec.The table list a 12 percent development reduction.I assume this is for a normal SBR.But what if I want to develop N-1, do I want to add this 12 percent on top of the N-1 reduction, so lets say I usually reduce 30 percent for a short exposure N-1, now I'm going to reduce 42 percent?