getting most out of C41 chemistry?

hi

i recently bought a jobo cpa-2 (same as cpe2?) and started my own c41 developing, have developed 6 rolls so far, looked good!

now i am quite uncertain how to handle the chemistry to get the most rolls out of it!

i poured the used chemicals (once 500ml for 4 rolls and once 250ml for 2 rolls) back to the bottle with the "fresh" solution, same with bx and stab

is this going to falsify my results by the time i reach lets say 12 rolls?

it somehow says 30 or 40 rolls of 35 or 120 on the package, but inside it says only 12 films per litre of solution... isn't this really just scre*ing the customer? the salesman said 30-40 rolls as well...

now whats to believe? how much am i going to get out of a c41 tetenal colortec kit for 1 litre of chemicals?

thanks for any information regarding this!

regards from vienna!

Yes.

You can use the same developer on multiple rolls across multiple dev sessions, but you have to extend the dev. times based upon the qty of film that has come before. I used this method in school, but I can not remember the formula. If you keep pouring the used developer back into the 'stock' then the stock will slowly become dilute and your results will become inconsistent and eventually worthless -- unless you get some replenisher and add it to the stock in accordance to the directions. Same with bleach and I'd just throw out the fixer as it is cheap enough and I'm not familiar with fixer replenishment.

regards from vancouver

I've got fixer "replenisher". It's the same stuff that's used up to make up my normal fixer just the mixing is slightly different.

Replenishing isn't that hard. So I replenish bleach and fix.

No replenishing is easy, I've just never done it for fix.

This solution capacity with rotary processing seems to be a vexed question with C41.

Kodak invented the process and the chemical composition other companies have made variations, I myself mix C41 from scratch, all are slightly different.

The official C41 capacity for 1l of developer from Kodak, is 4 rolls of 36 exposure, which isn't very much.

I believe that Tetenal products have a higher concentration of the colour developing agent, allowing a slightly higher capacity, what that is, if it is a fact even, I don't know.

Using empirical methods and having (at the time) access to control strips and a lab technician to read the developed strips, I found that with one shot processing on my Jobo CPE2 and 4 rolls of 36 frame film in 500ml of solution, I have excellent results which were inside the C41 control parameters.

Using that as a guide, I always end up processing 8 rolls per 1l of developer.

Rotary processing is different to deep tank developing and normal replenishment procedures. If you have a 4 litre deep tank and process 4 rolls of 36 frame C41, you will not come close to depleting the developer. At the end of the cycle you should replenish the bath by adding 52ml of replenisher developer per roll, which in this case would mean 208ml

However with rotary developing you are using (by comparison) minute amounts of developer and you effectively deplete the solution, it should be discarded. That is the official way, but I have cheated in the past and will occasionally do so.

In short there are so many methods used with excellent results, pick one that works for you and stick to it.

If you are able to get excellent prints from your film and have no colour crossover problems, then stay with your system.

30 to 40 rolls out of a 1l solution which is used undiluted, seems completely wrong to me. Maybe the label is partly wrong and is off a B&W developer packet by mistake?

Mick.

Tetenal advises 3 runs per working solutions.
The maximum/L and run would be 4 films 135, which means a total efficiency of 3x4films/L = 12films/L

The same comes true for the Amaloco or the Ornano chemistry for instance.

The developing (Blix) times for Tetenal (others give other times!) are:

1-4: 3`15`` (4`)

5-8: 3`30`` (6`)

9-12: 3`50`` (10`)

In addition Kodak relates the efficiency of their Flexicolor chemistry to the speed of the films developed.

I did not read such concerning other brand's chemistries.

I use 150ml per 120 roll or 36 exp 35mm of Kodak flexicolor LORR. I don't know if the low replenishment chemicals (LORR) are different. I am sure Ron (Photo Engineer) has posted before that Kodak used to give much higher rates of developing capacity than the current data sheets would indicate, and, that there has been no significant change in the formula. He even posted an old data sheet to confirm. I think he he uses only 100ml per film but don't take my word for it. I can tell you that 150ml gives great results. It also suits the capacities of the 1, 2, 5, and 6 reel 35mm Jobo tanks on the 2500 series that I use. For what it's worth, I wouldn't advise you to replenish your developer. You can however replenish your bleach and fixer using 3ltr pop bottles. Dan Schwartz has posted instructions on photo.net so I'd google it.

Just doing some lateral thinking here, AgX has displayed the different times for each successive developing run.

One possible problem could be if you do two lots of four rolls, at the different times as suggested, which makes sense to me.

But if on your third and final run you only have one roll to develop and you put it into the bath and develop it for 3'50" instead of the normal 3'15", you may be push processing!

Because the bath has the capacity to develop 4 rolls, but you are only developing 1, I think there may be a possible over development.

C41 developing is nominally 3'15", a push of one stop, is an additional 30 seconds, making it 3'45". I would think it is possible to accidentally push a roll, something to think about.

By the way C41 can effectively be pushed 2 stops, 3'15" is normal, 3'45" is a one stop push and 4'15" is a two stop push.

I have tried doing another 30 second push with various C41 films but it doesn't really work.

Mick.

Mick,

From a theorethical point of view all these time shedules fail, if you don't use them per full capacity each run.

If you would make two fresh working solutions of 1L and process manually 4 135/36 films in the one and only 1 135/12 in the other batch I'll guess you'll get different results.

However, in the latter case you would rather reduce the volume used to just the height neccessary for one reel, thus reducing the overdeveloping failure.

Thank you very much for all your answers.

So I am going to keep the used chemicals seperated from the unused, and use it 3 times perhaps cheat it and use it 4 times

I am looking for a more economical way to develop C-41 since it's over 5dollar a roll here in the lab, if I do it myself and use the tetenal kit 4 times, I can keep the cost under 2 dollars, which makes it possible for me to shoot twice as much for the same money

being in the film business without a steady income is not easy if you want to shoot a lot of film!

If your film is developed improperly, then you will lose detail. If the film is not properly fixed then it will fade fast. These two chemicals are relative cheap compared to the bleach. I use them as a one shot deal so that my film is fixed and developed with fresh chemicals.

On the other hand, the bleach is the most expensive part of C41 which runs about 27.00 per gallon not including shipping. I have talked with Kodak technical people and they said you could reuse the bleach once with no harm, but do not mix it back with the fresh stuff. Cycle through with the new bleach and collect it in a separate tank. Once the new is gone then reuse the saved solution only once. This will provide a savings of $13.00.

I would repeat my advice to use C41 in a jobo as one shot. I have Kodak flexcolor chemicals and at my usage of 150ml per roll we are not talking great cost for developer. Replenish your fixer if you wish, it will save you money on the most expensive component of developing. The trouble with reusing small quantities of c41 is that you will have small colour shifts in your negatives. If you are printing on to RA4 paper your filtration will be all over the place. I guess if you scan and print digitally the software will compensate for this.

Can somebody steer me in the right direction of developing my own 120 colour film. What is the chemicals I need and the process.
Thank you.

David,

If these are negative films (primarily to make prints from) you’ll need a kit of type C-41 chemistry, if these are reversal films (yielding directly a positive image, primarily intended for making slides) you’ll need a kit of of type E-6 chemistry.

Look for these at this forum and you’ll find some some informations about how to use them by hand (with an inverted drum and some temperature bath) as well by mechanical means (rotating processors).

There is no principal difference in developing type 135 films (35mm) and type 120 films. Basically you only need different (or differently adjusted) reels to spool the films onto for development.