Tmax vs. Tmax RS Jobo ATL Processing

[pompu]

Hi,<br>

I just started using my new Jobo ATL-1000 and at the same time,

started shooting 4x5 sheet films. Here are some of my questions.

<br><br>

- What are the differences between Tmax and Tmax RS? All I could

find was that RS is supposed to be used with sheet films. Does this

mean that it shouldn't be used with roll films? Should I use it for

tank processors, too?

<br><br>

- Should I use difference times for machines processing vs hand

processing? For example, I always used Tmax 5:30@75F for TMX, but

should I try different times for ATL processing?

<br><br>

- I've read that roll films and sheet films require different

processing times. Is that true for ATL processors?

<br><br>

- Why do we need different times and developers for Sheet vs. Roll

film, Hand vs. Machine processors? I couldn't find any descriptions

as to why this is required.

<br><br>

Thanks in advance!

<br><br>

Ted

[peter_witkop]

T-Max RS is the replenishable version of the developer, though many people (myself included) use it as a 1 shot developer. Regular T-Max developer is not recomended for sheet films because it has a tendancy to cause dichroic fog (see the john sexton <a href="http://www.largeformatphotography.info/articles/sexton-tmax.html">article</a> on t-max films, he mentions it and how to deal with it).

<p>

Machine processing in a jobo is continious aggitation, while hand processing is intermitant agitation; the differant processing times are because of the differant aggitation methods primarily. Most often the differances in times for sheet vs. roll films are due to the differances in processing methods.

<p>

Peter

[pompu]

Peter, it was interesting that T-max with sheet film could cause dichroic fog. Actually, I processed 6 sheets of TMX with my ATL-1000 yesterday, and it came out perfectly without any fog. <br><br>Does this mean the dichroic fog happens in certain cases only?

[peter_witkop]

My understanding was that it did not always happen, but I've never used t-max (not rs) developer with sheet film. I've heard the recomendation not to use this combo quit a bit (it is kodak's recomendation), but the sexton article was the first time I found an explanation as to why.

 

Peter