# Colour film developing issues



## jordi schoffelen (Dec 20, 2019)

Hi guys,  I'm new to this forum. Although I have been reading and enjoying the content the last couple of months, I've decided to join because I'm currently struggling with a bit of a problem I'd like to get your advice on. 

After developing BW film successfully for years now, this year I wanted to start a colour photography project. However, developing colour film does not seem to go that smoothly. On multiple occasions, both on 120 and sheet film I get these banding effect (see the examples below / these are straight scans and I can see the banding on the negatives as well). I have also included a digital contact sheet. 

I use kodak portra and kodak ektar film and develop with a tetenal c41 kit at 38 degrees Celsius. I use a Stark SST4 film processor and rotary development .

Can you maybe tell me what I may be doing wrong.

Thank you very much on your help!


----------



## jcdeboever (Dec 20, 2019)

Looks to like insufficient agitation of the film developer. When the agitation level is not high enough, depleted chemicals near the emulsion surface are not replenished in time to complete the development process and can accumulate and slide across the film. This retards film development in large areas causing streaks that compromise the integrity of the negatives.


----------



## jordi schoffelen (Dec 21, 2019)

Thanks for your insight. Could this be overcome by a) larger quantity of film developer (I only used the amount stated on the JOBO tank) and/or b) increasing the rotary speed?

Thanks again!


----------



## smithdan (Dec 21, 2019)

Certainly appears to be a chemistry issue.  Only used a tetinal kit once.  Powders seemed to dissolve fully.  Your rotary processor would manage consistant agitation.  Wonder if the film was somehow touching itself or the side of the tank.  Tetinal chemistry is reusable so filling your tank to capacity would be a good idea.


----------



## beddingfield (Jan 11, 2020)

Not to hijack the thread, but I have gotten a lot of this in film developed by Pro Photo. But for MY film... one side will be a shade darker. With black and white film like Tri-x 400, one side will be solid black.

Chemistry issue or just bad processing?


----------



## 480sparky (Jan 11, 2020)

Post some sample images so we know exactly that you're describing.


----------



## beddingfield (Jan 11, 2020)

heres a few saved on pc don't want to go digging for old negatives..


----------

