Strange coloured film base

Hi there can anyone tell me why I’m getting such different colour bases from Bellini and Adox c41 chemicals (Bellini left, Adox right) both hand developed in Paterson tank with all conditions exactly the same and chemicals around same age. Needless to say the Bellini scan a lot better.

It looks like the strip on the right suffers from excess cyan dye formation/fog.
Can you explain your development process in detail?
Was the ADOX chemistry fresh, or had it been used before?

koraks said:

It looks like the strip on the right suffers from excess cyan dye formation/fog.
Can you explain your development process in detail?
Was the ADOX chemistry fresh, or had it been used before?

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Hey thanks for the reply, the chemistry was new and I’ve stopped using it because of funny results over the last couple of kits.

With the adox:
Prewash film in de ionised water for 5 mins at same temp as dev

Dev: 3:15, invert for first 45 seconds and invert once every 15

Wash under running water 1:30

Blix 5 mins invert first 45 and once every 15

Wash under running water 6:00

Stab

Bellini:

Pre warm film in tank in water bath (dry tank)

Dev 3:15 invert first 45 then invert once every 15

Bleach 2 mins continuous inversion

Wash 1:30 under running water

Fix 3 mins continuous inversion

Wash 6 mins under running water

Stab

Filmandfile said:

Dev: 3:15, invert for first 45 seconds and invert once every 15

Wash under running water 1:30

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I would start by introducing a stop bath after development. It's OK to wash after the stop, but it's not a good idea to have a long water wash right after development. What will happen is that development continues as a result of developer remaining active esp. in the lower part of the emulsion (where the cyan dye is formed). If you introduce a stop bath, this prolonged developer action should stop immediately.

I notice that with the Bellini chemistry you go from development straight to bleach; the bleach is slightly acidic and strongly buffered, so it effectively also acts as a stop bath (it's deliberately engineered this way, too). So this may very well account for the difference you're seeing.

I have no experience myself with blixes for C41 film, and opinions are mixed. Some find it works just fine for them, others contend that they never get quite as good results with blix as with separate bleach and fix. However, I've never seen evidence of such major differences, so I don't think this in itself explains the issue you're seeing.

koraks said:

I would start by introducing a stop bath after development. It's OK to wash after the stop, but it's not a good idea to have a long water wash right after development. What will happen is that development continues as a result of developer remaining active esp. in the lower part of the emulsion (where the cyan dye is formed). If you introduce a stop bath, this prolonged developer action should stop immediately.

I notice that with the Bellini chemistry you go from development straight to bleach; the bleach is slightly acidic and strongly buffered, so it effectively also acts as a stop bath (it's deliberately engineered this way, too). So this may very well account for the difference you're seeing.

I have no experience myself with blixes for C41 film, and opinions are mixed. Some find it works just fine for them, others contend that they never get quite as good results with blix as with separate bleach and fix. However, I've never seen evidence of such major differences, so I don't think this in itself explains the issue you're seeing.

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Ah right I see, I was going by the Adox instructions, would you recommend an acetic acid stop bath?

Yes, that will generally work just fine. E.g. 1% acetic acid. The concentration isn't critical. Use it once, then discard.

koraks said:

Yes, that will generally work just fine. E.g. 1% acetic acid. The concentration isn't critical. Use it once, then discard.

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Thankyou, how long for an continuous inversion?

30 seconds would be OK. Technically, 10 should already be OK, so 30 seconds gives you a safety margin. There's not much benefit in a longer time, although up to a minute or so won't do harm either.

Okay, thankyou for your help!

Sure thing, hope it helps!

Filmandfile said:

Prewash film in de ionised water for 5 mins at same temp as dev

Click to expand...

This is a strong contender for the cause of the problems.

Unless you are measuring temp in and temp out and they are within tolerance, you are potentially causing crossover issues from uneven temperature, and/ or are potentially diluting the developer from carryover.

@Lachlan Young through which mechanism would this explain the excess cyan dye formation in the unexposed areas that we're seeing?

I would be REALLY surprised if either prewash or absence of stop after development would have such a huge effect.

brbo said:

I would be REALLY surprised if either prewash or absence of stop after development would have such a huge effect.

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Prewash, yes. Concerning the stop: if he would go from dev to blix, then I'd expect everything to be OK but with ramifications for the lifetime of the blix. But a 90 second water wash after development with carried-over developer is asking for problems.

koraks said:

Prewash, yes. Concerning the stop: if he would go from dev to blix, then I'd expect everything to be OK but with ramifications for the lifetime of the blix. But a 90 second water wash after development with carried-over developer is asking for problems.

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Thanks, I missed the 90s wash. That is quite long indeed.

I did a test a while back to see how big a difference a prewash and wash after development would make:

1. 30deg, 8:00
2. 38deg, 3:15 (standard C-41, no prewash, bleach directly after developer)
3. 38deg, 3:15; prewash, wash before bleach
4. 32deg, 6:30; prewash

If you compare rows 2 and 3 the difference is not even close to what @Filmandfile is experiencing. But, of course, I didn't wash for 90s, I don't remember how long the wash was, but definitely not longer than 30s.

Thanks for posting that @brbo, I think it's very interesting especially because I believe I see a hint more cyan in the orange base of #3 compared to #2. Gamma seems to be substantially higher, which is another hint that an intermediate water wash without a stop bath is not such a good idea if someone is after consistent results.

This is a crude inversion & edit of strips 2 & 3 to emphasize the difference in base color; note that strip #3 really is more red (i.e. more cyan dye). It's also a little uneven, with the effect being less pronounced in the middle of the strip and more so along the sprocket holes. Strip #2 doesn't seem to exhibit such unevenness, so I don't think it's e.g. a scanning artifact.

Yes, I agree with your observation. Differences are clearly noticeable.

Differences in OP are an order of magnitude more pronounced, though. But, as I said, I missed that OP did a very long wash.

koraks said:

@Lachlan Young through which mechanism would this explain the excess cyan dye formation in the unexposed areas that we're seeing?

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Firstly, I'd agree that the water rinse is not helping matters at all. However, the mask is where the problems appear most apparent. Ironically, the water wash might even be making the problem fractionally less bad than it might otherwise be.

The mask is comprised of yellow and magenta dyes spread across various layer groups (see diagram in Shanebrook), and there appears to be a significantly lower level of the magenta mask than there should be (which is in the deeper layers). If a pre-wash has dropped the temperature of the film even a little (or even created a temperature or dilution gradient within it), then development is not going to proceed as intended. The water wash, as you said, will allow the lower layers to continue to develop a little longer, however, there might also be a slightly higher level of retained silver from the blix process (well known as an inherent issue with blixes on film) that is helping to make density seem higher overall. As it is, dev straight into blix is the intended process. Even with a pre-wash that holds temperature correctly, development time would need to be extended, owing to dilution.

Lachlan Young said:

there appears to be a significantly lower level of the magenta mask than there should be

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I had to look twice as well, but before I proposed that the problem is in the water bath and lack of stop bath (or dev-to-blix without intermediate step), I had a good look at the posted negatives. I think what we're looking at is not reduced green density (lack of magenta dye), but higher red density (excess cyan dye). Look at this inversion with boosted contrast:


There may also be a slightly lower green density at the same time. But I don't think it's the dominant effect. In fact, if we only look at the green channel, there's no evidence of this issue:


The effect on the red channel is also too strong to be explained by retained silver as the result of a blix instead of separate bleach/fix. If film blixes were this bad, they wouldn't be sold even for amateur purposes and everyone using the ADOX kit would be running into this issue. We don't see reports of this.