Developing 4x5' negs ... continued

[jansenh]

Hello, APUG'ers!

In my possession I now have a Jobo drum (forgtot which modei it is). Anyway. it takes 5 pieces 4x5 sheets and consumes 300ml developer. I have a rollerbase for it.

My question is what kind of rotation is required?

 

[Nige]

round and round...

sorry...

 

[Robert]

Nige is wrong-)) It's a little one way. Then back the other way-)) If your base doesn't change directions then I think you're supposed to lift the drum up and fip it end over end every so often.

 

[jansenh]

round and round...

sorry...

;-/ Ahhh.... suddenly it all became obvious. The rotation is ... round. Didn't think of that.!

Anyone with an idea on what frequency - how many rotations per minute or second?

 

[Ed Sukach]

[/quote]
;-/ Ahhh.... suddenly it all became obvious. The rotation is ... round. Didn't think of that.!
Anyone with an idea on what frequency - how many rotations per minute or second?[/quote]

You apparently have one of the "3000" series tanks. According to the JOBO instruction manual for the CPP2, using a 3000 series tank, with 4" x 5" film, the rotation should be set at "F". I've never timed the frequency, but all I ever use with either 35mm or 120 film is "P" - which, if memory serves is about 75 RPM - or would be if the rotation did not reverse itself every two(2) revolutions. "F" is the slowest rotational speed available - and I am going to guess at about 30 RPM ... If it was "one way" ... etc. - see previous.

There is one instance - with 110 film - where JOBO does NOT recommend reversing rotation - and suggests that the reversing cam be "switched out of the way" so that the drum revolves in only one direction.

Now - my opinion, for what it is worth: I have an idea that the rotation, like the agitation of a hand-held tank, is not really all that critical. I'd start at about 30 RPM, and increase the rotation speed if I detected uneven development.

 

[MikeK]

[/quote]
Anyone with an idea on what frequency - how many rotations per minute or second?[/quote]

My Jobo CPE2 Plus rotates at 75 rpm and has bi-directional rotation. I have used the hand roller before the CPE and I just used a constant slide of the hand for 10 pushes one way they reversed the hand movement for 10 pushes the other. I used a 60 second pre-soak and stuck to the development times for inversion processing in a small tank.

I got good results and really strong wrists.

Mike

 

[galyons]

I use a Jobo CPP2 with both Expert (4X5) and 2500 series (MF). For B&W, I like ABC+ Pyro. Lowest rotation speed is about 22, I shoot for 25+/-. Formerly I used a CPE-2+. One speed 75. Quite honestly, I see little difference, if any at all, on the MF work between the two speeds.

Cheers,
Geary

 

[Robert]

Now - my opinion, for what it is worth: I have an idea that the rotation, like the agitation of a hand-held tank, is not really all that critical. I'd start at about 30 RPM, and increase the rotation speed if I detected uneven development.

Does this depend on the amount of developer in the tank? If somebody was using the bare min I'm thinking everything is more critcal.

 

[Robert]

I'm also wondering why people don't like the 2500 tanks for 4x5?

 

[Ed Sukach]

Now - my opinion, for what it is worth: I have an idea that the rotation, like the agitation of a hand-held tank, is not really all that critical. I'd start at about 30 RPM, and increase the rotation speed if I detected uneven development.

Does this depend on the amount of developer in the tank? If somebody was using the bare min I'm thinking everything is more critcal.

I don't think so. The idea of rotation is to take the place of agitation, and to prresent "fresh" or relatively so - chemicals to each individual area of the media.

There are minumum amounts of solutions needed to "cover" in processing - whether or not they are sufficient for processing is another consideration - but I don't think there is much of a link between the amount of chemicals and the rate of rotation/ agitation.

 

[Ed Sukach]

I'm also wondering why people don't like the 2500 tanks for 4x5?

Who? Which 4" x 5"? - film or paper? I don't have any information from the JOBO handbook suggesting the use of *any* 2500 series tank for 4" x 5" FILM.

Is it permissable/ done?

 

[Robert]

All the 2500 tanks work with 4x5 film. Just need the 2509N reel. Some people seem to not like it. I'm not sure why. Seems to work fine for me. It's nice that I can mix and match film in one tank.

 

[Jim Chinn]

I have used the 2500 tanks for 4x5 on my old CPE2 and never had any problem with even development. There is a minimum amount to cover the negatives which is 270 ml. I have always used 100 ml of stock solution for 80sq inches of film or 150ml for 6 sheets. The tank can hold 600ml of solution (although it will put a strain on the motor) so you can go up to 1-3 dilution with some developers if needed.

my habit is to do 4 sheets at a time with either Xtol or HC110 with a B or G dillution. I have never had satisfactory results with any kind of Pyro for drums so still do those in trays.

The only problem you may encounter is you need to load the film emulsion side in. Otherwise it is easy to scratch the outside sheets of film on the drum while loading in the dark and causing scratches.

it is not that difficult to load the sheets, just practice with some expendable negs untill you get it down.

 

[Aggie]

..