Perceptol 1 + 2 at 23, 24, 25 C

[Rob Hale]

Hi, Anyone know anything about Delta 100 and FP4 + & FP5 + in Perceptol in dilution of 1 + 2, times and temperatures. I have looked at the great big dev. chart and that lists the standard times & dilutions at 20 C ?? I find the emulsion can get a bit fragile at long developing times, perhaps I am a bit ham fisted ! so maybe 1 + 2 would suit me better ?
Anyone done any work with these films and Perceptol at 23 – 24 – 25 C ? It’s coming up to summer, here down under, and my cold water ( due to 400 meters of shallow buried in coming water pipe ) will be bouncing up over 21 C plus so it seems to me I should think of shifting my base developing temperature up. Up is simpler than cooling especially if I have a margin of 1 or 2 degrees.
Best Regards Rob

[Peter Galuszewski]

I would suggest going to the Ilford web site and pulling up the data sheet for the film or developer (or both) they should contain extrapolation tables for time vs temp above 20 deg C. They are actually printed on the inside of the perceptol box, as well. Just take the 20 time and let your finger do the walking. It will give you a pretty good starting point if nothing else.
Having said that, I don't like raising the temperature as Ihave found that it seems to contribute to grain - not really much of an issue in LF, but just a small format habit I got into. Also, I have been shooting the films you list extensively, and have found them to be very resiliant, with very tough emulsions - I don't even use hardening fixer, and have had no problems other than ones where I obviously messed up. And I have frequently used dilute developers which yield the 15min + dev times. It would be my humble suggestion that the time the negs spend in the soup is not the culprit vis a vis the emulsion damage issues.

[kev curry]

Hi Rob. I have no personal experience with this but I do know that the late Barry Thornton liked to use HP5+ rated at around EI200 in Perceptol diluted 1:2 for around 11 to 13 minutes at 24*C for a normal contrast scene.
This is from his book "Edge of Darkness".

Regards kev

[Rob Hale]

Hi Guys,
Thanks.
Peter humm I thought I might be the culprit, have work out why.
Regards Rob.