Do rotary processors affect how the film looks in the end? (tonality, film speed / shadow detail, etc.)

Craig · Thursday at 2:59 AM

Milpool said:
It was specific to developing Tech Pan roll films (small tank) in Technidol. The agitation instructions were to shake the tank up and down something like 10 times in 2 seconds for each cycle.

Tech Pan is a film that is very sensitive to agitation technique. Most general purpose B&W films are not nearly as sensitive to technique as TP is.

Craig · Thursday at 3:08 AM

dcy said:
Never thought of processing paper on a tube. I might give it a try. --- Still not gonna buy a Jobo, but as @GregY said, you can just roll the tube on the counter.

Tubes are great for large prints. A piece of 16x20 or larger needs to be handled very carefully to avoid creases. Bring the chemistry to paper in a tube, instead of the paper to the chemistry in trays helps ensure a crease free print.

For colour prints, tubes are about the only way to go for low volume use, or a roller transport machine for higher volumes.

Vetus · Thursday at 3:15 AM

From 1m 40" how to agitate by inversion

DREW WILEY · Thursday at 12:09 PM

Again, I didn't find Tech Pan fussy at all, in any film size. Technidol seems to have been the problem.

Sirius Glass · 2025-09-13T15:38:33-0400

MattKing said:
For clarity, there are two things you are attempting to accomplish:
1) you want to be sure that the development and other steps of the process are not uneven; and
2) you want to be sure that the results of the development and other steps of the process are consistent from roll to roll.
I find that the two hand method is good for ensuring both, because it is fairly easy to apply repeatably.
Repeatability is the strong suit of rotary processors - that is why I use it for most of my film development workflow.

I rate development consistency very highly.

GregY · 2025-09-13T15:41:54-0400

Sirius Glass said:
I rate development consistency very highly.

I find consistency is attained by repeated experience with one's chosen tools (no matter how simple or hi-tech) and workflow

Bill Burk · 2025-09-13T16:25:19-0400

dcy said:
Thanks!

If a picture is worth a thousand words, a video is worth a thousand more. I kind of envy people who learned this in the classroom. For a question like "how do you agitate", the teacher could say "let me just show you".

I'm going to follow your method from here on (except I'll use two hands because my tank is bigger, and invert a full 180° because that's just natural with two hands). That's more or less what I was already doing. I was also varying the direction that I inverted the tank in, but seeing your video and the comments from Matt and others, that's clearly not needed.

Thanks! And why view counts are meaningless. It’s who sees it that matters.

I mentioned uneven development.

First two frames of one of the rolls in that tank are I think shots taken pointing at the sky. When scanned, the scanner tried hard to create a gray balanced picture. You can see with contrast exaggerating the tones, the dMax varies. It would not be very evident in most prints except the top and bottom higher density tendency is visible in some pictures if you look for it.

p.s. Looks like a tiny bit of capping. I have been struggling with this ES-II and this is a tell-tale sign I need to go deeper into CLA territory than I wanted to go.

Vaughn · 2025-09-13T19:09:57-0400

Bill, looks like you have a little uneven developing happening around the sprocket holes holes, too.

Do rotary processors affect how the film looks in the end? (tonality, film speed / shadow detail, etc.)

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