Jobo tanks: What is the advantage of the 2500 tanks over the 1500

[Jerry Thirsty]

Hi all,

I've got a Jobo CPA-2 on the way, and am looking at what other equipment I might need to get for film processing. I've got a set of 1500 tanks and reels so that I can process up to 5 rolls of 35mm at a time. The seller of the Jobo is including a 2553 drum with 4 roll film reels and 2 sheet film reels. If I get another 2500 roll film reel I'll be able to do 5 rolls of 35mm in either tank. So is there any particular reason to use the 1500 over the 2500, or vice versa? The only thing I can think of is that the 2500 would be better for processes that require aeration. The difference in minimum chemical volume required is pretty small. Is there any practical benefit to reserving one tank for B&W and the other for C-41/E-6?

thanks,
Jerry

 

[Nick Zentena]

2500 4x5 and smaller sheet film.

I think the reels are easier to load.

You can sit a 2551 or bigger on a roller base when you need lots of chemicals.

 

[Iwagoshi]

Jerry,

I went with the 2500/2800 system so I can do film and up to 16x20 paper, without changing the roller set. Changing the rollers is not a big deal just something else that eats into the set-up time.

Terry

 

[Alan9940]

Hello Jerry,

Supposedly, the reels for the 2500 series film tanks, being quite a bit larger than the 1500 reels, allows for a more even flow of chemistry to the film surfaces. I own and use both 1500 tanks/reels and 2500 tanks/reels and have never noticed any discernible difference in the negs. Nowadays, I do tend to use the 1500 tank for 35mm and the 2500 for roll film mostly because the former requires less chemistry. In the past I've processed many rolls (120) of film in the 1500 tank and always have gotten beautiful, even development. I guess, in theory, the larger 2500 reels would be better for the processing of roll film using a pyro-type of developer whereby aerial oxidation is a concern. I wouldn't worry about it too much, though. It will probably come down to what's available for purchase...

Good luck!

 

[Chazzy]

Is it any easier to load 220 on the 2500 series reels, compared to the 1500 reels?

 

[Alan9940]

Is it any easier to load 220 on the 2500 series reels, compared to the 1500 reels?

I've never used 220, but I'd guess that, yes, it might be easier to load onto the 2500 reels since they are significantly larger in diameter. Therefore, I'd think the longer length of film would be easier to feed onto the reel.

 

[hal9000]

Here is an excerpt from a JOBO Dead Link Removed from 1999:

So which tank system should you select? It all depends on your particular needs. If you will be processing mostly 35mm film, go with the 1500 series. If you are processing mostly 120/220, either system will work, with a very slight edge in favor of the 2500 series. If you plan to process roll film and sheet film and don't want to spend the extra money for an Expert drum, the 2500 system is the answer.

 

[martin@jangowski.de]

Hi all,
So is there any particular reason to use the 1500 over the 2500, or vice versa?

The main advantage of the 2500 is more even development. The flow at the outside of the reel is stronger, so one end of the film gets more development. This is much more pronounced with the 1500, it has a very small inside diameter and a comparably larger outside diameter. The 2500 has less windings, so the differences are smaller (but easily measurable with a sensitometer).

Martin

 

[AgX]

Alan,

I don't get the idea behind your reference to aerial oxidation. (The smaller drum has got a smaller fluid surface.) Please explain your idea.

 

[Jerry Thirsty]

The main advantage of the 2500 is more even development. The flow at the outside of the reel is stronger, so one end of the film gets more development. This is much more pronounced with the 1500, it has a very small inside diameter and a comparably larger outside diameter. The 2500 has less windings, so the differences are smaller (but easily measurable with a sensitometer).

Martin

Ok, I see what you mean. It never crossed my mind before because I've always used inversion with my 1500 tanks. I have ordered the cog lid for the 1500, just in case I do want to try it.

The Jobo is supposed to be here tomorrow, so hopefully this weekend I'll be ready to try it out.

Thanks to everyone who responded,
Jerry