How much C-41 do I need to develop 2 rolls in one reel? How about 2 rolls in 2 reels (4 rolls)?

[moodlover]

So I have both the small Patterson tank (1x 120 reel) and the medium Patternson tank (2x 120 reels). I know processing one roll at a time just requires you to fill the tank up with enough liquid to cover everything. However, I'm trying to process more rolls at one time (2 rolls per reel, with 2 reels) and wondering how this affects the amount of chemistry I need?

1 roll = normal amount, 500mL
2 rolls in ONE reel = normal amount, 500-600mL
1 roll per reel x 2 reels on top of each other = 1000mL
2 rolls per reel x 2 reels on top of each other = ??? Would 1000mL still be enough? Or does it need 2000mL (500mL x 4 reels)?

 

[Lachlan Young]

With C41, it's a non issue - bear in mind that if a Jobo can process 2x135 or 2x120 films in 270ml of C41 & 5x135 or 6x120 in 660ml, you'll be more than OK.

 

[mshchem]

You can develop 1 roll of 220 in 500 ml, so if you can get 2 rolls of 120 on your Paterson reel. You're good to go with 500 ml. With Jobo they have the little red tab. But I've loaded 2 rolls of 120 on a Paterson reel. It can get a bit confusing in the dark.
I use Jobo but I still usually use 1 reel for each roll of 120
Best Regards Mike

 

[Mick Fagan]

When doing C41 in the past, I worked on 8 rolls of 135 or 120 per litre. As I develop using a Jobo the most economical way for me to process was to use a tank and module configuration that allowed me to develop 4 rolls of 135 or 4 rolls of 120 at once in 500ml of solution. To do the same 4 rolls with inversion as you are attempting to do, I would need to use 1,000ml of solution. I did sometimes use inversion agitation with C41 to develop 4 rolls of film at a time.

To develop 8 rolls by inversion, I would develop the first 4 rolls, then clean everything and dry the reels, then use the same (used) solution to do the second batch of 4 rolls of film, usually within 30 minutes of finishing the first batch of film. Essentially the chemistry won't go off if you re-use it as quickly as possible after first use. Within 4 hours would be perfectly alright from my experience. Leave it a day or so and the chemistry seemed to break down, whatever happened, running a control strip through a day later and it was obvious the C41 chemistry wasn't on song.

Most of the kits available in the 80's through to the 90's, whether they were the small 1 litre or 2 litre or the more economical 5 litre kits, gave 8 rolls of film per litre as the absolute maximum for quality of development. Quite a few of my friends doing C41 would do more rolls per litre, but from about 10-11 rolls per litre onwards, quality went down. I know this as I had access to Kodak C41 control strips and developed the control strip then took it to my work where it was checked and measured to the Kodak standard.

At 8 rolls per litre, the control strips were on the money, at 10 rolls per litre, the edge was just starting to be met,but certainly alright, from 11-12 onwards, the control strips were off.

Here you can learn a little about control strips. It will probably be technically over your head, but you will get the gist of what they do and why they really tell you about how your C41 developer is working.

http://www.kodak.com/global/plugins/acrobat/en/service/Zmanuals/z131_05.pdf


Mick.

 

[mshchem]

When doing C41 in the past, I worked on 8 rolls of 135 or 120 per litre. As I develop using a Jobo the most economical way for me to process was to use a tank and module configuration that allowed me to develop 4 rolls of 135 or 4 rolls of 120 at once in 500ml of solution. To do the same 4 rolls with inversion as you are attempting to do, I would need to use 1,000ml of solution. I did sometimes use inversion agitation with C41 to develop 4 rolls of film at a time.

To develop 8 rolls by inversion, I would develop the first 4 rolls, then clean everything and dry the reels, then use the same (used) solution to do the second batch of 4 rolls of film, usually within 30 minutes of finishing the first batch of film. Essentially the chemistry won't go off if you re-use it as quickly as possible after first use. Within 4 hours would be perfectly alright from my experience. Leave it a day or so and the chemistry seemed to break down, whatever happened, running a control strip through a day later and it was obvious the C41 chemistry wasn't on song.

Most of the kits available in the 80's through to the 90's, whether they were the small 1 litre or 2 litre or the more economical 5 litre kits, gave 8 rolls of film per litre as the absolute maximum for quality of development. Quite a few of my friends doing C41 would do more rolls per litre, but from about 10-11 rolls per litre onwards, quality went down. I know this as I had access to Kodak C41 control strips and developed the control strip then took it to my work where it was checked and measured to the Kodak standard.

At 8 rolls per litre, the control strips were on the money, at 10 rolls per litre, the edge was just starting to be met,but certainly alright, from 11-12 onwards, the control strips were off.

Here you can learn a little about control strips. It will probably be technically over your head, but you will get the gist of what they do and why they really tell you about how your C41 developer is working.

http://www.kodak.com/global/plugins/acrobat/en/service/Zmanuals/z131_05.pdf


Mick.

Very Good Advice!
Mike