Tetenal C41 developing question

[Tmea]

Greetings,

im new to the forum (incredible resource) and new to developing color at home. I'm looking for some observations or advice on using the Tetenol C41 kit. I bought the powder based kit, mixed the chemicals and went at it. First two rolls came out very well now I'm getting negatives that are very dark and lack contrast. I've processed six rolls of 24 exp 35 mm.

I think I've kept the significant variables in check so far. Temperatures are right ago 102, chemicals are stored in collapsing bottles with no air gap. Rinse funnel and measuring cup to reduce cross contamination, followed the directions and times etc.. I cannot identify where the problem may be. The chemistry is about two weeks old.

The only thing that comes to mind is one of timing and developer deterioration. The instructions call for 3:30 developing time across the life of the kit (12 rolls of 35mm). It occurs to me that with each use the developer loses some of its effectivness and thereby should require a corresponding addition to the enveloping time beyond 3:30. There is nothing in the instructions that address this, nor have I found anything else on the net. I'm out of answers.

would appreciate any shared wisdom or recommendations you may have

thanks!

Tom

 

[zehner21]

May we see a photo of the negative?

 

[Sirius Glass]

Welcome to APUG

How much time between the first two rolls and the next six?

 

[fotch]

Welcome to APUG

"chemicals are stored in collapsing bottles with no air gap" Note! These bottles are suspect. I use to use them myself however, the type of plastic used doesn't stop air from infiltrating the bottle. May or may not be your problem. JMHO

 

[wildbill]

First off, you'll need to spell tetenal correctly for an effective search. Search "re-use c41" or re-use tetenal c41
Lots of info on the web about this.

 

[Photo Engineer]

Dark negatives with low contrast sound like your bleach and fix or blix have gone bad or have been used up.

PE

 

[mablo]

I add 15 seconds on top of the developing time for every 4th or 5th roll. It's not anything scientific. I simply try to keep a somewhat standard contrast level as the developer gradually becomes weaker.

 

[Photo Engineer]

See the Kodak chart on C41 with the increases in time needed to develop more than one film. If you overdo it, you might be fogging the film.

PE

 

[bvy]

This seems to be coming up a lot lately. Persoanlly I think it's hard to troubleshoot C-41 developing problems when you're reusing the developer. Everytime you open that bottle and start dumping it here and there, you're introducing all kinds of variables and potential problems. In general, I think it's fine to re-use the developer, but for trying to diagnose problems, you could be chasing your tail.

 

[Lamar]

Do a two minute rinse (fill and drain multiple times preferably) after the developer. It's not in the instructions but it helps with x-contamination. I usually do about 8 to 10 rolls before I call it quits for a batch but I have done more if the chem's shelf life doesn't catch me. I've stretched it to 4 weeks before tossing it though and still got decent results, in my experience things get a bit questionable after that. For storage I just use old 1 liter drink bottles and have had no problem with any accelerated degradation...... but every time I look at my pictures I want a Coke....

Disclaimer: I scan only so I figure that can hide a multitude of sins. You mileage may vary significantly if you're printing optically.

 

[Photo Engineer]

If you do anything after the developer do a 1 minute or 30 second stop bath with 2% Acetic Acid.

PE

 

[Rudeofus]

First two rolls came out very well now I'm getting negatives that are very dark and lack contrast.

How did you come to the conclusion that your negs have low contrast? Is this just your impression from looking at the negs, or did you try an optical test print which came out flat? Note that retained silver will reduce color saturation, but not contrast, because silver builds up in the same areas where dye clouds form. Also, in my experience every fogged negative looks low in contrast regardless of its actual contrast.

I'd say take a test clip of your neg and try to rebleach it, either with some fresh BLIX, or mix yourself a quick batch of Farmer's reducer. If density doesn't go down, your developer was too active. I know that p-Phenylenediamine and its derivatives (e.g. CD-4) go up in pH over time, and as a result developer activity (and fog) goes up.