Jobo 2840 for 5x7 film developing?

**campy** · 18-Mar-2018, 04:39

I am going to look at the Jobo 2840 today $35 and would like to know if this will be ok to develop 5x7 film or should I pass and get something else. Is there anything I should check? I only have 2 film holders so I wouldn't be doing more than 4 sheets.

**Jimi** · 18-Mar-2018, 06:49

It works fine for me (using a 2830), put the emulsion inwards. Others might have other opinions - mostly the develop-in-a-tray gnomes. (just kidding, folks!)

**photonsoup** · 18-Mar-2018, 19:08

It has worked well for me with black and white. I haven’t tried color

**AuditorOne** · 18-Mar-2018, 22:50

The 2840 drum will develop up to 4 5x7 prints.

Jobo does not recommend that you use any of their 2800 series print drums to develop film as there is not enough solution flow behind the surface of the film to totally eliminate the anti-halation layer on the back of the film because of the ribs in the drum that prevent the paper from sticking to the inside surface of the drum.

Obviously you will read posts where people do develop film in them but it could backfire and Jobo does not recommend it.

**koraks** · 19-Mar-2018, 01:23

It's a common misconception that the antihalation dye is at the back of the film. In most films, it isn't: it is embedded into the emulsion, in a layer below the silver halide image forming layer(s). So for the majority of films, flow of chemicals across the back of the film is unnecessary. I've tried developing 5x7 in a jobo print drum and the antihalation dye washed out fine.

**campy** · 19-Mar-2018, 04:31

I went and looked at the drum and didn't buy it. It was very large and I think maybe a couple of the BTZS tubes might be better for the few I will be doing. I may also just do one at a time with my mod 54 drum. If I use my mode 54 drum for one sheet at a time will I have a problem reusing the chemicals a second time?

**John Layton** · 19-Mar-2018, 06:39

...steadfast "develop-in-a-tray-gnome" here - and proud of it!

**photonsoup** · 20-Mar-2018, 19:03

Originally Posted by AuditorOne

The 2840 drum will develop up to 4 5x7 prints.

Jobo does not recommend that you use any of their 2800 series print drums to develop film as there is not enough solution flow behind the surface of the film to totally eliminate the anti-halation layer on the back of the film because of the ribs in the drum that prevent the paper from sticking to the inside surface of the drum.

Obviously you will read posts where people do develop film in them but it could backfire and Jobo does not recommend it.

I had heard this, but before I got the Jobo I made some BTZS type tubes from ABS pipe. They worked fine and the film is literally sealed to the inside wall of the pipe, If the film has a annihilation layer on the back, I just soak the developed negative in a tray of water and it clears off. Occasionally I'll need to soak a 5x7 negative that was done in a 28** drum. But I've never had a negative ruined buy it. Ive done a lot of 4x5s one or two at a time in a 2821 test drum and all have worked very well (even with only 40ml of developer).

**AuditorOne** · 30-Mar-2018, 12:10

Originally Posted by photonsoup

I had heard this, but before I got the Jobo I made some BTZS type tubes from ABS pipe. They worked fine and the film is literally sealed to the inside wall of the pipe, If the film has a annihilation layer on the back, I just soak the developed negative in a tray of water and it clears off. Occasionally I'll need to soak a 5x7 negative that was done in a 28** drum. But I've never had a negative ruined buy it. Ive done a lot of 4x5s one or two at a time in a 2821 test drum and all have worked very well (even with only 40ml of developer).

Thanks for the clarification. I have always avoided using my 2840 drum for developing negatives based on this warning. I guess I should have looked into it a bit closer rather than just accepting the warning at face value.

I will certainly give this a try, particularly as it can be used for 11x14. 11x14 trays take up a lot of room.

**Laurent L** · 15-Apr-2018, 02:20

Hi ! I Also process my 5x7" and my 13x18cm film sheets in a Jobo 2830. The results are most of the time OK but sometimes the sheets are moving and things get messy. I got a precious piece of advice that may be useful : to prevent sheets from sliding and to place them with more precision, you may need some Jobo clips. They are available on catlab website. I Bought some after understanding how they worked I will gladly share my experience with you as soon as I receive them.