Jobo Development and Drums

[roscoetuff-Skip Mersereau]

Thank you again.

Another item in John Finch’s book that i guess slipped by me earlier is the idea that development for scanning (i.e. hybrid for ink printing) should be done from negatives under developed to hold the density back almost 30%. Wow! Really? Just as mentioned the oft recommended shorter rotary development times are in practice subjective, i guess i can’t say i’ve really seen this given… though that i haven’t tested it either. Thoughts? I’ve listened to comments that we want lower contrast for scanning… but hmmm.

[Alan9940]

I’ve listened to comments that we want lower contrast for scanning… but hmmm.

Been scanning all formats of film from 35mm to 8x10 for 20+ years on flatbed and dedicated film scanners and I've never modified my development times for scanning. I use the same tested development times whether scanning or printing in the wet darkroom.

[roscoetuff-Skip Mersereau]

Would love the idea of a knock-off smaller 3000 series / style drum that would fit on the same machine. The 2509 reels even with the loader seem more reliable with 4 sheets… and plenty have confirmed this as it is just easy for 2 sheets to inadvertently touch and ruin the process. Once is one time too many… changing the idea behind exposure bracketing into “a dupe in case i screw up the 2509 reel.” Who needs that?

Last thought: I’m increasingly convinced the larger tanks in the 2500 series may just be too much for the machine and 2 reels of 4x5 - even with only 8 sheets - might under developer the effort. Will have to check this when i get back from out of town. C41 with 3 rolls of 120 works fine, but that’s a different issue suggesting i redo / recheck the math. Just thinking out loud.

[Larry Gebhardt]

Thank you again.

Another item in John Finch’s book that i guess slipped by me earlier is the idea that development for scanning (i.e. hybrid for ink printing) should be done from negatives under developed to hold the density back almost 30%. Wow! Really? Just as mentioned the oft recommended shorter rotary development times are in practice subjective, i guess i can’t say i’ve really seen this given… though that i haven’t tested it either. Thoughts? I’ve listened to comments that we want lower contrast for scanning… but hmmm.

I can’t see the benefit for sheet film. I believe the idea is you get smaller grain with less development. However you lose film speed and the ability to print with an enlarger. You also are stretching the data more from the scanner to get a full range of tones. Any good scanner should be able to handle the limited density of a normally developed negative, and even one developed for alternative processes. After all velvia blacks are denser than any negative you are likely to produce and most scanners can almost handle those.

[Larry Gebhardt]

Would love the idea of a knock-off smaller 3000 series / style drum that would fit on the same machine. The 2509 reels even with the loader seem more reliable with 4 sheets… and plenty have confirmed this as it is just easy for 2 sheets to inadvertently touch and ruin the process. Once is one time too many… changing the idea behind exposure bracketing into “a dupe in case i screw up the 2509 reel.” Who needs that?

Last thought: I’m increasingly convinced the larger tanks in the 2500 series may just be too much for the machine and 2 reels of 4x5 - even with only 8 sheets - might under developer the effort. Will have to check this when i get back from out of town. C41 with 3 rolls of 120 works fine, but that’s a different issue suggesting i redo / recheck the math. Just thinking out loud.

For 4x5 in an expert drum you normally have plenty of room for developer, assuming your machine can handle the weight. For example the 3010 will process 10 sheets, which is equivalent to 2.5 rolls of film. The tank can hold a full liter, which is about the limit for most Jobo processors. The 3005 is another story. It holds 5 8x10 sheets, which is only 200ml per roll/sheet assuming you limit volumes to a liter. Most diluted developers need more than that even before you add in extra oxidation from rotation.

[Vaughn]

...The 3005 is another story. It holds 5 8x10 sheets, which is only 200ml per roll/sheet assuming you limit volumes to a liter. Most diluted developers need more than that even before you add in extra oxidation from rotation.

One easy way of handling that is to do two developer runs.

[Larry Gebhardt]

One easy way of handling that is to do two developer runs.

Do you just swap out the developer part way through for fresh? Are the times the same that way?

[Vaughn]

There will be slight differences (time to drain out the first batch, 2nd dev might be a little more active, etc), so some slight adjusts might need to be made -- I did not worry about it. Unless you are doing incredibly tight work such as masking, color separations and such, you might not see any difference.

[ic-racer]

https://www.largeformatphotography.i...essing-Rodinal

[Peter De Smidt]

I use Jobo Expert drums for LF development. They work great, and they are very easy to load. I haven't used the reels for LF..... If they are way cheaper, then I recommend buying one and giving it a try. If your results are good, then you're all set. Check for evenness of development and extra edge density. One sheet expose to say an even Zone V should tell you a lot. I used to use Xtol at up to 1+3, as Kodak had development times for that. I never noticed a problem. I mainly developed 5-4x5 of TMX sheets in 1 liter of developer.