View Full Version : PMK vs. HD
steve simmons
8-Apr-2004, 14:56
I now have a batch of HD to try and compare with PMK. My questions is the realtive developing times. For example, if my time for film X is 10 minutes at 68 degreees what should be the time for HD with the same film and temp.
steve simmons
John Sarsgard
8-Apr-2004, 15:30
I am also interested. I've heard that HD works well at somewhat higher EIs than PMK. If anybody has starter times/EI for HP5+ I'd appreciate knowing.
Mark_3632
8-Apr-2004, 15:41
A lot of this information is at APUG.org and michael and paula's AZO forum thingy. On Apug search for pyrocat or the film type. Hope this helps.
For most films your development time for Pyrocat-HD at the same temperature should be about .75 to .85X PMK times. In other words, if PMK time is ten minutes Pyrocat-HD times should be 7.5 to 8.5 minutes. These times are for silver printing with graded paper with the 1:1:100 dilution. Some slight adjustment may be required for VC papes.
These times are based on my tests and on the formula as published in the formulae section at http://www.unblinkingeye.com/. This is important to note because in my formula the Stock B solution is a 75% solution of potassium carbonate. Some of the small Pyrocat-HD kits distributed by Formulary appear to have provided directions for a 100% solution of potassium carbonate, which makes a slightly more energetic, or fast acting developer.
steve simmons
8-Apr-2004, 18:15
Thanks Sandy. I got my developer from Bostick and Sullivan.
steve simmons
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