[quote="Dave Swinnard"]An update on the agitation issues with Jobo & Pyrocat HD:

HP5+ in Pyrocat HD 1+1+100 in the Jobo double reel tank with 306 mls of solution showed slight signs (to the same degree) of "sprocket hole" agitation artifacts at both the slowest (28 rpm) and "normal" 75 rpm setting.

I looked through a bunch of literature and everything I have indicates that the kinds of development artifacts you describe are the result of over-agitation. So for whatever reason it appears that using the Jobo at 28rpm is still too fast for the Pyrocat-HD working solution being used, even though this speed may work fine with other developers.

Are the artifacts a result of stain? I suspect this may be the case since you mention that the artifacts are more exaggerated with TRI-X than with other films, and for some reasons both TRI-X and TMAX-400 develop a lot more general fog with fast rotation than other films.

My advice at this point would be.

1. Slow down the rotation to 10-15 rpm.
2. If you can't slow down the rpm add a pinch or two of sodium sulfite to the working solution directly before use. This may correct the problem if the artifacts are due to stain streaks.
3. If neither of the above corrects the problem you need to use another developer, or change to another method of development.

Did you mention that you had developed 35mm film in Rollo Pyro and not seen the artifact problem? If so this is an anomaly that really surprises me because in every comparison I have made of Rollo Pyro with Pyrocat-HD the latter has been more cleanly working and much less likely to cause any kind of uneven development.