C41 processing - where did I go wrong?

bestbefore1978 · Nov 20, 2017

Hi,
I’m looking for some help as to what I’ve done wrong tonight processing two rolls of C41 (i’m fairly new to the process)

Mixed up fresh chemicals - Bellini C41 1 litre kit with separate bleach and fix.

1st film (Superia 200) processed absolutely fine, strong orange base, good contrast, strong edge markings.

I washed out and dried the tank, re loaded and went again

Exactly same process, temp, agitation (I am using an automated processing machine)

2nd roll (Portra 400) - extremely thin, barely developed, little colour with a murky brown base.

I’m not sure what went wrong! The machine pumps the chemicals back into their respective chambers, and then runs the same sequence again, so I definitely didn’t mix up the stages.

I’ve tried re bleaching and re-fixing but no difference.

Any clues?

bvy · Nov 20, 2017

Can't view your image.

bestbefore1978 · Nov 20, 2017

Sorry, here, bad one on left

Photo Engineer · Nov 20, 2017

Looks like no bleach or fix.

PE

bestbefore1978 · Nov 20, 2017

I did think the times quoted in the instructions were on the short side (45 seconds bleach , 1.30 fix) at 38 deg C.

But then the first film came out fine with the same times.

All 3 chemicals came back dark red after the first film, but I assume that is just the anti-halation later washing out?

Thanks

Photo Engineer · Nov 20, 2017

Bleach is up to 6 minutes with a 2 minute wash after, and fix is up to 6 minutes with a wash up to 2 minutes. Then the final rinse solution.

Dyes in the film color the developer (or prewet if you use one) and the bleach will color the fix if the wash is insufficient. The final rinse can often become red due to bad washing. The bleach is normally red or green depending on type. If you had green, and it is now red, it has probably gone bad due to carryover of developer or overuse.

PE

bestbefore1978 · Nov 20, 2017

Thanks for the advice Ron, The kit i’m using must be quite unusual I think, here are the instructions that came with it; very short times for bleach and fix, and suggested not to rinse between stages

https://ntphotoworks.com/shop/wp-content/uploads/2017/03/KIT-C-41-english_NT.pdf

The bleach was green and pre-mixed whereas the dev, fix and stabiliser needed to be diluted to a working solution prior to use.

Photo Engineer · Nov 20, 2017

I can't download that due to a local problem, but I understand what you have.

Here are the Kodak recommended process cycles and capacities for C41 authentic chemicals.

PE

bestbefore1978 · Nov 21, 2017

Thanks for that. I think i’ve worked out why the bleach time is 45secs, the kit contains C41 RA bleach, which is the more aggressive one?

Rudeofus · Nov 21, 2017

If you run in small tanks, liquid carryover can be significant. I once measured, that a small Jobo tank for 135 rolls carries over 10 ml if you spend some time pouring out the very last droplet that would come out, and quite a bit more if you pour quickly. If you consider how little process liquid goes into such a tank, you will see how much these liquids get contaminated or at least diluted with every reuse.

Arbitrarium · Nov 21, 2017

Did you pre-soak the Portra? Not sure if it would make a difference, but when I developed Portra the pre-soak poured out really dark green/brown, and the negs developed fine. Maybe it needs soaking?

bestbefore1978 · Nov 21, 2017

Thanks both, I didn't do any pre-soak, pre warmed the tank dry in the water bath.

Rudeofus - I think you may be onto something here, this specific kit I am using states that you should not wash at all in between steps, and go straight to stabiliser outside the tank after fix.
Because the machine wasn't 'flushed' with a wash cycle, perhaps what happened was that when I run the machine the second time is that residual fix in the pipes and valves inside the machine contaminated the developer as it was pumped into the tank?

Would a small amount of fix such as this completely ruin the C41 developer?

Rudeofus · Nov 21, 2017

This would not be "a small amount of fix". Carryover of 10 ml into a tank that takes less than 250 ml, and considering that fixer is basically 10-15% Thiosulfate, turns your CD into a developer heavily loaded with strong silver solvent. In addition to that, fixer for color processes is typically buffered at pH 6.5, therefore your contaminated CD ran at lower alkalinity than it should have.

bestbefore1978 · Nov 21, 2017

This makes sense now, I'm sure this is what has happened. I am using a 500ml tank, but without a full wash after the fix, some must have got into the developer on the next run. I will try again with fresh chemicals, luckily I split the 1L kit down into 500mL bottles.

Is the developer the most sensitive solution to contamination? Is there the same issue with dev carryover into the bleach stage as well or is this more tolerant?

Rudeofus · Nov 21, 2017

Developer is quite sensitive for two reasons:

This is where colors are formed - i.e. your actual image
You can re-BLIX, rebleach, refix as often as you want, and if the first attempt went awry, the second, or third, or tenth attempt can save the day. There is no such option if CD step is messed up for whatever reason.

Photo Engineer · Nov 21, 2017

The instructions you quote are from a RA process for throw away negatives with no wash. This process is for direct to scan negatives. It is based on little carryover due to using a process machine type will little carryover, and therefore the first negatives in your process are OK, but from subsequent runs they get less and less acceptable. The instructions I gave are for the tank process for "keep" negatives. I think that is the source of the problem.

PE

Sirius Glass · Nov 21, 2017

PE as always has located the root cause of the problem. Thank you @PE.

bestbefore1978 · Nov 21, 2017

Photo Engineer said:
The instructions you quote are from a RA process for throw away negatives with no wash. This process is for direct to scan negatives. It is based on little carryover due to using a process machine type will little carryover, and therefore the first negatives in your process are OK, but from subsequent runs they get less and less acceptable. The instructions I gave are for the tank process for "keep" negatives. I think that is the source of the problem.

PE

Thank you PE for your advice, I will replace the bleach with a more suitable type and run a proper sequence with wash steps as per your attachment

C41 processing - where did I go wrong?

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