I'm planning to start out with hand-inversion processing of 4x5 sheet film and am stuck between the MOD54 (in a Paterson 3-reel tank) vs. the Jobo 2509n (in a 2520 2-reel tank).
Aside from the additional flexibility/modularity (and easy 4x5 loading) of the Jobo, and assuming my inversion technique would be identical for both systems, why is it that the Jobo, which seems to be a smaller tank (accepts 2x 35mm reels), requires nearly 1.5L of developer for inversion processing whereas the MOD54 requires only 1L in a (seemingly) larger 3-reel tank?
Additional questions:
a) can you adjust the amount of developer downward when processing (by hand inversion) less than 6 sheets of film in each of these two tank systems? Say, if doing 4 sheets, or if doing 2 sheets, rather than 6? Do you still have to use 1L for MOD54 and 1.5L for 2509n?
b) how does the above answer change with rotation processing on the Jobo? The website says: "High efficiency; run as few as two sheets of 4X5 with no waste of chemistry." Having a hard time understanding what that means. Isn't the minimum volume for rotary processing 270ml? According to what I've read here, that is the same minimum volume needed for 6 sheets. If so, that means the tank is NOT efficient for 2-sheet processing, since you'd be able to get 4 additional sheets out of the solution if you maxed out the 4x5 reel. What am I missing about their claim that it's a "high efficiency" tank?
I am a complete newbie (first post here at LFPF!), so I'm sorry if I'm missing something super basic. Tried researching this topic but couldn't find an answer to these nagging questions.
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