Going to Jobo.. what do you think?

[brian steinberger]

From my previous forum, on being new to PMK, I've decided to try the Jobo 2521 tank with the reel that holds up to 6 4x5 sheets. Even if I decide against using PMK, I will still use it to process all my 4x5 film. I can use it hand inverted, which I plan to, or I can use it on a roller base. Seems like a good choice for 4x5 and a good switch from using tanks and hangers. What do you think?

[Nick_3536]

It needs about 1.5litres of solution for inversion from memory. If that doesn't bother you then no issues I can think of. Personally I'd suggest the 2551 tank instead. The 2551 will fit an unicolor or beseler motor base. The 2521 is too small and not very much cheaper.

[Peter Lewin]

Two comments: First, the 1.5 liters mentioned in the previous post is probably less than you would use for tray developing; I typically tray develop 4x5 film in an 8x10 tray with 2 liters of solution. But PMK is so highly diluted that you are using very little chemical in those two liters. For inversion processing in a tank, be aware that PMK really "froths up" - I develop my 120 film in PMK in Patterson tanks using inversion, and you have to be very careful with the inversions to avoid getting a very aerated solution (you can feel when the liquid stops moving in the tank!) You minimize this by adding EDT per Gordon Hutching's book.

[brian steinberger]

I see that the 2551 is not much cheaper at all. Does the 2551 take 2 reels of 4x5 at 6 sheets per reel? If PMK froths up so much, then simply doing one reel of no more than 6 with just enough developer to cover that reel (using inversion) would leave plenty of room for frothing. Any opinions?

[Jay DeFehr]

My opinion is that you'd be better off using 510-Pyro, all around. You can use any tank or drum you like with 510-Pyro, and get better negs in the bargain.

Jay

[Nick_3536]

The 2551 takes two 2509N reels [the sheet film reels] or 5 2502 [the 35mm reels] or a combination.

[merlo.luca1961@libero.it]

Brian,

I had the same problem when I started to develop 4x5 films. I needed a quick, reliable system that could allow me to develop several 4x5 negative without the usage of a machine. After several unsuccesful trials with a JOBO 2521 modul by inversion system that ended in several uneven negatives, I decided to process the film by manual rotation with the same tank. The results were even worse since the tank cannot be rotated adequatly on a plane surface since the lid is protruding and the tanke cannot be obviously properly rotated on a plane surface. This inconvenience can be easily solved by using the JOBO 2521 tank coupled with a 2560 modul. The modul, which is connected on the upper part of the JOBO 2521 render the entire system "even" and it can be rotated without any problem on a piece either on the floor or on a piece of plywood. The system, if equipped with three spirals, will allow you to process 18 negatives at a time using a quite small quantity of liquid (I personally use 1.200 cc but you can definitely use a smaller quantity). I rotate the tank back a forth at 80 rpm and I am getting excellent and consistant results without using any roller or any bulky and expensive machine. The system is so good that I have now three units of this type and they allow me to process 54 negatives in a developing session.

[ronald moravec]

To invert a jobo you need the non cog lid, which is different from the cog that connects to the lift.

You need 1200 cc PMK and as it is a slow fill, Put 1000 in, add the loaded reel in the dark, cap, lift out and replace twice, add the lid, add the last 200 add the small cap. Invert 1 time every 15 sec. Ok to pour out thru the cap but it takes 20 sec.

Actually this is an excellent way as is any sealed tank for PMK which oxidises very fast if exposed to air. Times are 2/3 that of open trays as the developer stays fresh. It will come out looking just like it went in instead of brown/red.

I found this the best way for 4x5 sheets or I use a Nikor 4x5 tank. It is like an overgrown 35mm tank. 12 sheets require 36 oz.