Dichroic fog with TMax dev + sheet film? How much a problem?

I've searched here and elsewhere on this subject. It's well documented that dichroic fog can form on sheet film when developed in TMax developer, hence Kodak's recommendation NOT to use TMax dev for sheet film. Kodak recommends TMax RS developer for sheet and roll films, as it's formulated to prevent dichroic fog formation on sheet film. Evidently this isn't a problem with either developer on roll film.

I can recall many years ago having dichroic fog form on 4x5 film developed in TMax (not RS) in one of those daylight intermittent-agitation sheet-film tanks. The tank was a hunk of junk, frankly; I do all my film processing in a Jobo with continuous agitation nowadays.

It also seems that the two developers are different animals, with the most frequent complaint being that the RS version is much contrastier (whatever that means, taken out of context.)

What are your experiences? I'm doing both 120 and 4x5 in the Jobo. How much a problem really is dichroic fog? Any idea whether the continuous agitation of the Jobo might make dichroic fog less likely using TMax (not RS)? And what are your impressions of the differences between the two developers in terms of image quality?

Thanks all.

Good Morning, Mike,

There are some threads here on APUG where this topic has at least been mentioned, although I don't recall seeing any detailed discussion of it.

As I have previously posted, the dichroic fog problem has never come up for me. Years ago, I discovered that I had missed the Kodak warning for T-Max Developer and sheet film. By that time, I had processed hundreds of sheet in the regular T-Max without the slightest problem. I have continued to use the regular T-Max for both roll and sheet film since that time and have had excellent results. I process all sheet film in a Chromega drum on a motor base, but I doubt that the processing method would make any difference; my T-Max developer dilution is 1:7.

My speculation (and that's exactly what it is, since I lack any knowledge of chemistry) is that differences in water quality from one area to another might account for the fog which some users have experienced.

Why not try some sheet film in regular T-Max? If you have no problem, just ignore the Kodak warning; doing roll and sheet film in the same developer means one less chemical to handle in the darkroom.

Konical