Hi Tom:
I admit to being a bit surprised about your problems with PCHD and the Jobo. Although I am developing most of my film by inspection using PCHD, TMax cannot be DBI because of a coating on the film. When I develop the "new" TMax 400 in the Jobo I tend to follow Sandy's advice and procedures as he has posted. Such suggestions follow:
<One of the big advantages of Pyrocatechin is that it does not oxidize as rapidly in alkaline solutions as Pyrogallol. However, with very active agitation, as in Jobo at maximum speed, Pyrocat-HD does indeed oxidize. For this reason I recommend very slow rotation to minimize oxidation when developing film in Jobo processors.
My recommended procedures for rotary processing are straightforward and conventional.
1. Start by loading the film into the tubes or drum. With some drums and tubes it may be necessary to load the film wet to make sure there is a transfer of chemicals on the base of the film.
2. Pre-soak the film for five minutes. Distilled water is recommended.
3. Discard the pre-soak water and pour the developer into the drum or tubes and begin development. I recommend a minimum of 50ml of the 1:1:100 dilution per 4X5” sheet of film (20 square inches). This amounts to about 90ml for 5X7, 200ml for 8X10, 385ml for 11X14, 300ml for 7X17, 600ml for 12X20, and 1200ml for 20X24. Remember, these are minimum amounts. With the 2:2:100 dilution the amounts can be reduced by about 20%.
4. Adjust your procedure as follows depending on whether you are using Jobo, BTZS type tubes, or print drums on a motor base.
Jobo — Rotation speed should be at the slowest setting available. This is very important because fast rotation will result in a large increase in general or b+f stain. If it is not possible to slow down the rate of rotation there are other options that will also reduce the amount of general stain. The degree of oxidation that can take place in an alkaline Pyro developer is controlled by the amount of sodium sulfite preservative in the working solution. With most forms of development Pyrocat-HD needs very little sulfite to prevent excess general stain and it is provided by the small amount of sodium bisuilfite in the A solution, which serves two roles: 1) the sodium bisulfite acts as a preservative in the stock solution, and 2) when it mixes with the potassium carbonate alkali it forms sulfite through reaction. However, when we develop film with rotary processing at high rotation rates the amount of sulfite is insufficient and general stain can result.. To counter this I recommend one of the following solutions: add 30% more of stock solution A when making up the working solution, or (but not also) add about 0.3 g/L of sodium sulfite to each liter of working solution. Both solutions have the practical effect of bumping the amount of sodium sulfite preservative in the working solution and this will slow down the rate of oxidation.>
Best of luck. Please let us know if Sandy's suggestions solve the problems you shared with us.