View Full Version : Divided Pyrocat and Ilford Delta 100

Jan Becket
6-Oct-2017, 23:07
Iʻve been happily using divided Pyrocat HD in glycol for years with Kodak T-Max 100 (in a JOBO ATL 1500), but my local camera shop stopped carrying TMX and now carries Delta 100. It is way less expensive these days, so I picked up a box and expected to make a few tweaks and come up with something workable. Not so much, at least not yet. The film yields accurate shadow details at full speed (100). When I place something at zone 3, thatʻs what I get. However the highlights are off the chart.

TMX 100 appears to respond differently to divided pyrocat, with the developer acting like a genuine compensating developer. I rarely need to worry about highlights, even in bright sun. So far, with Delta 100, the highlights are way beyond reasonable levels, even though I have 1) reduced the divided developing times to 4.5 minutes in each bath and 2) decreased the strength of the solution A and B solutions from my usual 1:20 to 1:25 and then to 1:30.

Itʻs beginning to look like the Pyrocat HD & Ilford Delta 100 do not play well together and I need to abandon this effort - or try another developer entirely. Anyone else had success with that particular combo?

Steve Sherman
7-Oct-2017, 14:28
Greetings, I abandoned the Divided technique and returned to Cat HD using Extreme Minimal Agitation technique and can assure you that Delta 100 and PyroCat HD perform wonderfully, in my experience about 15% less development time is needed with the D 100 versus FP 4

2 cents

7-Oct-2017, 17:51
One of the major differences I observed in testing different films with divided Pyrocat is that some have emulsions that can absorb more of the reducer in the first solution than others at a given temperature and time of development. If the film absorbs a lot of reducer in the first solution, it will develop to a higher contrast. The difference is due to the thickness of the gelatin emulsion and/or the hardness of the gelatin in the emulsion.

Ilford Delta 100 is a film that I never tested with divided Pyrocat. However, the fact that it develops to high contrast with a 1+20 or 1+30 dilution of the solutions is actually a very good thing in that it indicates that the emulsion is capable of absorbing a lot of the reducer. To develop to a lower contrast, just try a weaker dilution, say 1+40 or 1+50, or even more dilute as necessary.

For printing optically, or contact printing with large format film, I would personally opt for the EMA references by Steve.
For scanning film and printing digitally or with hybrid method via digital negatives, divided Pyrocat offers a simplified exposure and development system that gives very high acutance.


Pere Casals
8-Oct-2017, 12:51
Very interesting information

Jan Becket
10-Oct-2017, 19:29
Sandy, Steve, thanks for the information. I appreciate learning something about the variable absorption of divided Pyrocat in different emulsions. That explains a lot. Since I scan my negs, there is an incentive to make this work.

Iʻve doing some tests over the past few days and so far things begin to look reasonable when I peg the film at 50 asa and dilute solutions A and B at 1:60, with five-minute times for each solution. Thatʻs just a point of departure which may get refined, but the negs look good enough for me to feel confident in making some images.

11-Oct-2017, 17:22

You may have seen it, but if not let me point you to a general article on two-bath development at the PyrocatHD web site.


For many years I did nearly all of my exposure and development with BTZS methodology, but when I began scanning and printing digital negatives for my work with alternative printing processes I switched to two-bath development.


Jan Becket
8-Nov-2017, 01:42
I did see that article when I originally began to use divided Pyrocat in my Jobo. Excellent piece.
I did some further real-world testing and have modified the dilution for Delta 100 to 1:40. Actually, in my case 1:37.5, since I add 8ml each of A and B to 300ml water. The earlier dilution I tried was ok in full sun but not in low light. The optimum ASA still seems to be 50. Iʻve attached a couple of image files from the test. I adjusted the middle levels slider in Photoshop but otherwise left them as is. (The lens is a SA 47mm XL.)
- Jan