PMK vs. HD

[steve simmons]

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]

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]

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.

[sanking]

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]

Thanks Sandy. I got my developer from Bostick and Sullivan.

steve simmons