JOBO processing if your a student..

[Liam:]

Hi,
I just bought a jobo 2500 series tank and 4x5 holder to develop 4x5 film. My main problem is that I don't have a motor base, so I was thinking of making one out of lego

I see it being relatively easy but I am unsure of what speed I should set it to, am I right in thinking it is 60rpm?

Up till now I have been using the taco method with inversion using these times..

Fomapan 1:100 10mins (rodinal)
Ilford FP4 1:50 14mins (rodinal)

Will the times stay the same for rotation developing? I have read that switching direction stops streaking, is every 30 seconds ok?

Thanks for any help.

[savantcreative]

I think you can go slower than that to keep the grain smaller. 30 seconds seems about right. I used to own three Jobos-the big floor model and 2 portables. One was a manual dump. I got great results running color transparency film in them. Best of luck.

[NicolasArg]

Hi Liam, I've been in a similar situation several months ago, perhaps something in this thread will help you:
http://www.largeformatphotography.in...ad.php?t=66570

[Brian C. Miller]

Believe it or not, people were rolling the drums back and forth on their counters. When Jobo heard about that, they developed the roller base, which is just rollers. You can make one yourself from furniture casters.

[Liam:]

Believe it or not, people were rolling the drums back and forth on their counters. When Jobo heard about that, they developed the roller base, which is just rollers. You can make one yourself from furniture casters.

Hi Brian, that was my initial idea but then I remembered that I have 3 brothers and a box full of lego. It would take me (maybe them) a few minutes to come up with something that could a spin a drum at a constant speed.

[Daniel Stone]

IDK about Lego plastic and photo chemicals. Could be a fun project .

but If I were you, I'd go to your local hardware store, buy a 6"x12" piece(cutoff maybe) of plywood, and screw some casters(non-rotating base) to it.

this way, you can manually turn it.

or, you can get a unicolor/beseler motor base, preferably a self-rotating one so you don't have to stand at the counter the whole time, flipping the tank to change the direction of rotation.

-Dan

[Lachlan 717]

Old skateboard trucks work well due to their wheels' width.

[Liam:]

Wood/casters / skateboard trucks may be easier but with lego I can have it motored very easily.

[seabird]

Hi,

Up till now I have been using the taco method with inversion using these times..

Fomapan 1:100 10mins (rodinal)
Ilford FP4 1:50 14mins (rodinal)

Will the times stay the same for rotation developing? I have read that switching direction stops streaking, is every 30 seconds ok?

I've never used Fomapan but I do process FP4+ in Rodinal 1+50 in a Jobo 2551 tank. Bear in mind that agitation is one of the variables that will impact development when using Rodinal (refer df cardwell's article on APUG). You haven't told us how many inversions per minute you use with your taco processing regime, but I anticipate that if you use constant rotation in your Jobo you may find your development time needs to reduce. I'd recommend testing the new setup before you use it for any important negatives.

As a matter of interest: I expose my FP4+ at EI64. I then process in Rodinal 1+50 for 7.5 mins at 20 degrees C. I rotate by hand using a homemade "skateboard" roller base as referenced in an earlier post. I usually swap ends halfway through the development time. I can only think of one possible streaking problem - if that is, in fact, what it was (still not sure).

Best of luck

[Liam:]

Hi Carey, that is very helpful. I am currently agitating every 30 seconds for 5 seconds (full inversion) I did have a feeling that I would need to reduce developing times.