Cinestill chems & blank rolls...

Hey everyone,

New to the forum and analog photography. I've thus far developed 20 rolls successfully using my Cinestill C41 quart kit, but yesterday experienced my first time pulling out entirely blank rolls. While I know developer and chemicals can expire (these were in air tight, compressable storage for 3 months...so stretching it), I had used them just a week prior and they worked fine.

Has anyone else experienced such a steep drop off / "death" of their chemicals? I would have thought since the last four rolls developed came out fine, that at the least these would have been faded rather than completely blank. The film was loaded properly as well, so no miss fires or mistakes there. Just came out entirely blank.

I now have Tetenal C41 liter kits (I live in Sweden, so this is all available here atm) and intend on developing 5 rolls at a time with ideally 15 in total as the kit affords 12-16, but doing this much closer together in time (not keeping chems for 3 months).

Looking forward to hear if anyone has experienced the same, any tips for me going forward, etc. Thanks in advance!

Were the blank rolls black or clear ? Black means bad chemicals - clear means bad camera or film simply wasn't exposed.

The C41 chems should last longer than three months if you've only developed four rolls, if it was a one litre kit. A one litre kit can do 10 rolls at least, and over six months is not unreasonable as long as the chemicals are stored correctly.

All I can say is; I'm glad I tested my part-used chemicals with this control strip before I used them!

My reference control strip just revealed itself after hiding from me.

This is what the strip above should have looked like in good chemistry:

Top is the Kodak processed reference, and bottom a strip processed in Tetenal chemistry. The Tetenal strip is slightly over-developed and the base doesn't appear to have cleared properly. It still printed OK, but it's not ideal. I've had results much closer to the reference strip.

Were the blank rolls black or clear ? Black means bad chemicals - clear means bad camera or film simply wasn't exposed.

 

The C41 chems should last longer than three months if you've only developed four rolls, if it was a one litre kit. A one litre kit can do 10 rolls at least, and over six months is not unreasonable as long as the chemicals are stored correctly.

In total this batch of chems had developed 20x rolls. These two were numbers 21 and 22. I read that if the roll comes out clear, and you cannot see the side markings that indicate the film type, then it's chems --- and that if you can see the film type markings but zero photos, you messed up in exposing/loading. This is contrary to what you're saying though, so not really sure which to think upon.

All I can say is; I'm glad I tested my part-used chemicals with this control strip before I used them!

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Interesting. Never even heard of test strips before. Will read up on those. thanks.

I read that if the roll comes out clear, and you cannot see the side markings that indicate the film type, then it's chems --- and that if you can see the film type markings but zero photos, you messed up in exposing/loading.

You read correctly.

I think kmac was suggesting a third possibility - completely black film, i.e: fully exposed. handling issue or chemistry.

The Tetenal strip is slightly over-developed and the base doesn't appear to have cleared properly.

Whoa!! That's an understatement. I used to oversee QC in a lab running 40, maybe 50 control strips per day. If that strip is anything like the snapshot looks like, we wouldn't be letting that film processor start up. If no one knew what went wrong there'd be chemical samples going to our chem lab while another control strip is running through the machine. This is (was) in high-volume commercial processing where stuff is not allowed to be wrong; obviously hobbyist use can work under different standards, especially if scanning. High-quality optical printing is a bit more demanding on the film processing.

Interesting. Never even heard of test strips before. Will read up on those. thanks.

There's plenty of info in Kodak's Z-131 manual, section 5. When the results are graphed with red, green, and blue lines, here's what's happening: the film has three different color layers. They're sensitive to (roughly) reddish, greenish, and bluish light, and result in dyes that are roughly opposite (complementary) to the exposing light; the dyes are called cyan, magenta, and yellow. The test strips are read with an instrument called a color densitometer; this has the ability to "see" into a section of film and measure the individual dye quantities. Then the result is plotted, using red to represent cyan due, etc. Higher density numbers mean that more dye is there, meaning that clear film has low density values; dark film has high density values.

Using control strips is something most hobbyists won't wanna bother with. They're relatively expensive and require a densitometer to do it up right. Without a densitometer you might as well just shoot your own reference negatives, then periodically process one for visual comparison.

Whoa!! That's an understatement. I used to oversee QC in a lab running 40, maybe 50 control strips per day. If that strip is anything like the snapshot looks like, we wouldn't be letting that film processor start up.

Yep, it was pretty much as it looks there, but remember you're seeing double the density difference because the strips are just lying on a sheet of paper, not a lightbox.

The developed densities are slightly heavier than the reference, but it's the base colour and density that's way off. IIRC I put the actual film back through a fresh blix bath and it cleared considerably.

I only kept a few control strips that were indicative of an issue. The good ones were nearly all disposed of.

I later changed to a different brand of chemistry, which was a huge improvement in consistency over the Tetenal kits. Having said that, Tetenal was probably the best of the 'big brand' small-quantity kits after May & Baker went out of business. The others were either total garbage or uneconomically expensive.

In total this batch of chems had developed 20x rolls. These two were numbers 21 and 22. I read that if the roll comes out clear, and you cannot see the side markings that indicate the film type, then it's chems --- and that if you can see the film type markings but zero photos, you messed up in exposing/loading. This is contrary to what you're saying though, so not really sure which to think upon.

There's a variety of ways things can go wrong.

Developer causes a dye image to be formed, as a following step to developing a silver image. If the developer is completely "dead," then these won't form. The fixer should then remove all the undeveloped silver, leaving a clear (actually orangish) film. On the other hand, if the developer has been contaminated with bleach, the entire roll will be very dark, even the unexposed parts, with a heavy cyan cast.

If you DO see the edge-print numbers, this is proof that the developer is at least somewhat functional. It's also possible to have problems with the bleach and fixer; these are responsible for removing the silver from the film, leaving only the dye image. But these usually function at least somewhat; the only thing that "commonly" goes completely dead is the developer.

As a note, even developer doesn't go suddenly dead, although it might appear to over a period of several days. What would probably be happening is that the developer would be in the process of going bad, but you don't notice it. For example, the actual developing agent might be largely gone, likewise the "preservatives" that protect it from being oxidized. (A lab running control strips would clearly see the developer activity falling off, but a casual user maybe not.) Then, with no more preservative left to protect it, the reduced amount of developing agent might just be finished off during a week or so of non-use.

Overall, the safest thing to do is to "test" the developer immediately before processing any important work. But overall, it may not be worth your time to do this. If you have a history of successful processing you might have an idea of how your developer holds up over time, so you might have a lot of confidence in it up to a certain amount of aging. So you probably wouldn't want to spend the time to do a test run for everything. On the other hand, if you had spent a large amount of money to hire models and stylists, etc., then you would probably prefer to do a test run ahead of time. It just depends on how important things are.

IIRC I put the actual film back through a fresh blix bath and it cleared considerably.

Yep, that's always the saving grace for a marginal bleaching step. It doesn't usually happen with a separate bleach and fix, at least for hobbyist quantities, cuz the mere act of pouring bleach back and forth helps to aerate it.

Fwiw, the control strip has a really sensitive test for bleaching (but you need a color densitometer to see it; but likely a scanner would do also). Basically you look at, as I recall, the yellow dye layers in both the "black" and "yellow" patches. If there is a bleaching weakness it will begin to show first in the black patch, where all three color layers are heavily exposed. By comparing to the pure yellow exposure any developer effects are mostly nulled out, so you can see a bleaching weakness long before it has a visible effect on "normal" film. In high volume processing the bleach has to be aerated constantly, so such a test is useful. If something happens to the air supply - maybe the airflow is reduced - and the operators don't happen to notice, then the control strip is a backup check.

A second thing that can cause higher "stain" levels in the clear film is related to the aeration. In the standard process, film goes directly from developer into bleach. So a certain amounts of carryover developer gets into the bleach. If there is excessive carryover (maybe a squeegee is misadjusted) and the aeration is excessive, then oxidized developer in the bleach can cause a high stain level. Obviously this wouldn't usually happen in non-machine processing, but is just an example of non-obvious things that can happen.

To be sure, you are increasing development time depending on how many rolls have been processed?

As I understand it, the official list says 12 rolls (120 or 135-36) per quart/litre

for unreplenished use.

In total this batch of chems had developed 20x rolls. These two were numbers 21 and 22

After 20 rolls (35mm) the developer would be exhausted. The 21st and 22nd was taking it too far for a 1liter kit, even 20 was a stretch.

Now that you know what the capacity is of that Cinestill kit is, you can now set your own limit of the number of films to process. You could set the limit at 20 if you like but maybe something less would be less risky for the tail-end of that limit. If you were to set your limit to 18, you could be sure then that all 18 will be good, provided the chemicals were stored well with no oxygen in the developer bottle and kept in cool ambient temperature. When you reach the limit you set for a 1litre kit, toss the chemicals and have a fresh kit ready to be mixed. That will save all the worry of wondering how further films will turn out.

Last I did C41, I mixed up 240ml batches from liquid concentrates, and used it for three rolls.

So, 20/quart is five rolls/240ml.

I don't see the actual instruction sheet on the Tetenal site, but it should have the times.

Basically you look at, as I recall, the yellow dye layers in both the "black" and "yellow" patches. If there is a bleaching weakness it will begin to show first in the black patch, where all three color layers are heavily exposed.

Thanks Bill, that's useful to know if I ever do any C-41 again. However I'm sure my box of control strips are well out of date and useless by now, even though they've been fridged. Also my densitometer is only a B&W model, even though I fudged it to read colour densities by making a tri-colour RGB LED source.

Making your own test strips could be done by photographing suitable density/colour patches on an LCD monitor screen. The tricky bit is ensuring that your reference strip is properly processed in the first place.