8x10 HP5+ Reciprocity Chart

[Daniel Grenier]

I have switched to 8x10 HP5+ and I have NO clue what the behaviour of this film is past the 1 second mark. So, I'd appreciate you letting me know what you have found to be proper reciprocity compensations with this particular film (exp.& dev. compensations that is). Any other concerns I should have with HP5?

Thanks for your recommendations.

[tim atherton]

have you checked the reciprocity graph from Ilford for HP5...?

[Daniel Grenier]

I did, Tim, but I do not typically trust manufacturer's recommendations on much - if anything. I'd rather rely on "real world" opinions such as those found in this group.

[tim atherton]

I've generally either gone by the chart or my other rule of thumb, which is guess.

[steve simmons]

Here are my adjustments

1=2, 2=4, 4=7, 8=19, 12=33, 16=50, 24=93, 32=145

steve simmons

these are seconds

[David Karp]

If Steve Simmons' numbers are the same as the ones in his book, I have found them to be accurate. From memory, they look pretty much the same to me.

[Edward (Halifax,NS)]

Steve, are you sure about 4=7? It doesn't fit the rest of the series. It is the only time that is less than double. Don't mind me. I spent too much time in math class.

[steve simmons]

I took these numbers from my book. I can't explain the seeming inconsistency. These numbers are the ones i use and they seem to work.

steve simmons

[Sal Santamaura]

In Photo Techniques' July/August '03 issue, Howard Bond provided results of some extensive long-exposure tests he conducted. I believe HP5+ was among the films he evaluated and, given the time frame, should have been the latest "improved" version of that emulsion.

[Philippe Gauthier]

The figures given reflect the graph in the Ilford data sheet; from about one stop to 1.5 stop up to twelve seconds; about two stops in the 12-25 seconds range; and 2.5 stops after 25-30 seconds.