MikeMGB
Well-known
I did a search on this and found little real information.
I started doing C-41 at the beginning of this year using a Unicolor C-41 kit and developing at 20°C.
I just developed my 19th and 20th film in the same kit that had been mixed for 6 months. I have been increasing development time slightly as I used it to compensate for the chemicals aging and the last film out looked as good as the first film out. However, after those two films I dumped the chemicals, I will start again with a fresh set.
Did I do the right thing or could I have carried on using the chemicals for a while? What happens to the film when the chemicals get too old or exhausted?
I do keep the chemicals in collapsible bottles, for the first three months I kept them in the fridge, after that I didn't bother.
I started doing C-41 at the beginning of this year using a Unicolor C-41 kit and developing at 20°C.
I just developed my 19th and 20th film in the same kit that had been mixed for 6 months. I have been increasing development time slightly as I used it to compensate for the chemicals aging and the last film out looked as good as the first film out. However, after those two films I dumped the chemicals, I will start again with a fresh set.
Did I do the right thing or could I have carried on using the chemicals for a while? What happens to the film when the chemicals get too old or exhausted?
I do keep the chemicals in collapsible bottles, for the first three months I kept them in the fridge, after that I didn't bother.
nukecoke
⚛Yashica
I had Tetenal C41 1L working solutions in normal glass bottle in fridge for one year and 25 rolls developed in it. The last 5 rolls had signs of weak developer. I dumped them after 25 rolls.
FujiLove
Well-known
As far as I'm aware C41 is fairly resilient once mixed, as long as it's kept away from oxygen. RA4 chemicals even more so. There a few threads over on APUG where people have experimented and achieved double or more films from the chemicals than the manufacturers state. However, they usually see some deteriation in density and eventually colour shifts. These can usually be compensated for at the scanning stage if you're using a hybrid workflow. Not so good if you're wet printing.
I usually dump my chemicals after hitting the manufacturers guideline number of films, or slightly less. My reasoning is: what's the point in risking ruined film to save a few pounds when almost all my photography costs are related to travel.
I usually dump my chemicals after hitting the manufacturers guideline number of films, or slightly less. My reasoning is: what's the point in risking ruined film to save a few pounds when almost all my photography costs are related to travel.
dmr
Registered Abuser
I've been trying to get a handle on this information too, and I'm getting numbers that are all over the place! I just started doing C41 at home so I'm no expert and I'm still on my first kit. Here's what I think are sane numbers:
Refrigerated mixed chemistry: A few weeks.
Refrigerated opened chemistry: A few months.
Refrigerated unopened liquid chemistry: A year at least.
Any disagreement?
Refrigerated mixed chemistry: A few weeks.
Refrigerated opened chemistry: A few months.
Refrigerated unopened liquid chemistry: A year at least.
Any disagreement?
MikeMGB
Well-known
tonyc
Established
Oxygen is the killer for these chemicals, not temperature.
Keep them in filled glass bottles with protectan gas to stop oxidisation.
Number of rolls is usually stated in by the manufacturer, beyond that
you will not get optimum results, but for some people that is less of
an issue than for others.
Keep them in filled glass bottles with protectan gas to stop oxidisation.
Number of rolls is usually stated in by the manufacturer, beyond that
you will not get optimum results, but for some people that is less of
an issue than for others.
x-ray
Veteran
I can't believe what some of you do. This is the crowd that fussed over their Leicas and lenses or Nikons and then cheap out on processing. I would never let you touch my film.
Going outside the recommended life and capacity results in speed and contrast loss plus crossover in color. I have a lot of professional experience with color processing and I'd never think of doing these things if I value my images.
Oxidation occurs not only from exposure to air it's a result of the process itself. Development is a reduction / oxidation process. As the silver halide is reduced to metallic silver the development agent is oxidized in the process. This oxidation has nothing to do with exposure to air. This is one of the reasons there's a film capacity recommendation.
Go by the manufacturers recommendations if you value your images. On the other hand you might not care or be able to discern the difference.
Going outside the recommended life and capacity results in speed and contrast loss plus crossover in color. I have a lot of professional experience with color processing and I'd never think of doing these things if I value my images.
Oxidation occurs not only from exposure to air it's a result of the process itself. Development is a reduction / oxidation process. As the silver halide is reduced to metallic silver the development agent is oxidized in the process. This oxidation has nothing to do with exposure to air. This is one of the reasons there's a film capacity recommendation.
Go by the manufacturers recommendations if you value your images. On the other hand you might not care or be able to discern the difference.
x-ray
Veteran
What you have to do is decide if your you care what your images look like and if you're willing to risk turning your images into trash.
I'm amazed! I'm scolding folks for putting this kind of stuff out on the internet. People that are trying to produce fine images will read and follow it. This is why you shouldn't believe most of what's on the internet. Next year will be my 50th year as a full time commercial photographer. This is one of the many reasons photography is at the lowest quality in my 50 years.
I'm amazed! I'm scolding folks for putting this kind of stuff out on the internet. People that are trying to produce fine images will read and follow it. This is why you shouldn't believe most of what's on the internet. Next year will be my 50th year as a full time commercial photographer. This is one of the many reasons photography is at the lowest quality in my 50 years.
michaelwj
----------------
While I agree with X-ray (in theory) sometimes it is convenient to do it a little differently. For example, I had 12 rolls of C41 to develop (over 2 days), the box says 10, and there are reports of people getting up to 40 rolls with a formula to calculate the new development time. Also there are varying reports of the time you can keep the mixed solutions, in particular the blix in the unicolor kit reportedly goes off quickly.
So back to me, I wasn't going to just develop 10 rolls and then mix and discard another batch just for 2 rolls, that just seemed wasteful*. I extended it out to 12 rolls and the 12th roll was as good (or bad) as the first. I put the chemicals in the fridge after that - they've been in there for a week now but I wouldn't keep them for much longer, maybe another week or so.
In general, I find on top of chemical degradation, if I keep chemicals for too many rolls (even if the box says I can) then I start to get solids precipitating out of the solution back onto my film.
*I try not to be wasteful in general. Film development chemicals are bad enough for the environment as it is so I try to eek as much out of them as possible. I figure if I can get twice as many rolls out of the kit then I'm dumping^ half the chemicals.
^By dumping I mean disposing of properly, but they still need to be manufactured and disposed of somewhere.
EDIT: To appease X-ray: I'm not a professional and just do it for my enjoyment. If you really care about the quality of photography then don't listen to me.
(that should be in my signature...)
So back to me, I wasn't going to just develop 10 rolls and then mix and discard another batch just for 2 rolls, that just seemed wasteful*. I extended it out to 12 rolls and the 12th roll was as good (or bad) as the first. I put the chemicals in the fridge after that - they've been in there for a week now but I wouldn't keep them for much longer, maybe another week or so.
In general, I find on top of chemical degradation, if I keep chemicals for too many rolls (even if the box says I can) then I start to get solids precipitating out of the solution back onto my film.
*I try not to be wasteful in general. Film development chemicals are bad enough for the environment as it is so I try to eek as much out of them as possible. I figure if I can get twice as many rolls out of the kit then I'm dumping^ half the chemicals.
^By dumping I mean disposing of properly, but they still need to be manufactured and disposed of somewhere.
EDIT: To appease X-ray: I'm not a professional and just do it for my enjoyment. If you really care about the quality of photography then don't listen to me.
(that should be in my signature...)
x-ray
Veteran
Two extra rolls, there's a safety margin most likely but 40 or even 20! No i wouldnt. Pro or not, if you care about your work you follow the instructions.
dmr
Registered Abuser
There's more than one over at APUG who claim to be getting good results doing some fairly extreme dilution (like 9:1 of the recommended working solution) for one-shot and getting several times the supposed capacity of the chemistry.
I've been thinking about trying one-shot doing a fairly conservative dilution, as in just enough to adequately fill the tank, but have not tried it yet. I've been mixing 8oz at a time and doing 2-3 rolls with each batch.
MikeMGB
Well-known
I highly doubt anyone interested in ultimate quality is going to read what I posted and follow my method, they would know better.
I take photographs in two ways, I shoot black and white using mostly Leica and Zeiss equipment. I also play with a large collection of oddball cameras for fun. I use colour film in cameras like my 1916 and 1935 box brownies, my 1920s Kodak folders also get colour film - it's just what I do.
My black and white developing is done with quality in mind, one shot developer, fixer tracked and documented to make sure it is still at its best.
C-41 I want to stretch to the limit, because I can, trust me, a colour film shot through a 101 year old lens doesn't need professional dip and dunk processing!
x-ray
Veteran
You have to explain what you're doing and why. No one can read your mind. As far as people taking things like this seriously, some people do. There are a lot of people that know nothing and take information seriously. This is a way of spreading really bad information.
Seriously I don't understand why people who don't know go to sources where people know little to no more than the person asking the question. Why not go to the source where the technical experts can give the correct answers? How many times have I seen questions answered by, "I've never used **** but I think you should ***." They should be directed to the recommended information from the manufacturer.
Seriously I don't understand why people who don't know go to sources where people know little to no more than the person asking the question. Why not go to the source where the technical experts can give the correct answers? How many times have I seen questions answered by, "I've never used **** but I think you should ***." They should be directed to the recommended information from the manufacturer.
mwoenv
Well-known
I like the Unicolor kits and I've gotten up to 19 rolls from a 1 liter kit. However, I save up these rolls and developed them all within several days. Unicolor instructions warn that the chemicals should be used within several days - blix starts to degrade quickly, even when stored in fully stoppered bottles and in the dark.
Maybe results by developing with older chemicals is alright for you if you are scanning negatives and can make adjustments relatively easily as you get different negative densities and colors as the chemicals age. But if you are doing RA4 printing, you really want consistently developed negatives to avoid having to adjust the enlarger color filtration and exposure time constantly. I know the 19 rolls developed in a few days are consistently developed because I can use the same enlarger settings from negative to negative and roll to roll, making adjustments only if there was some special lighting or exposure conditions.
As far as extending to more rolls, 20 rolls equals $1 per roll - what more do you want, why chance poor results, considering the costs of your camera, traveling to places to shoot, and film?
Maybe results by developing with older chemicals is alright for you if you are scanning negatives and can make adjustments relatively easily as you get different negative densities and colors as the chemicals age. But if you are doing RA4 printing, you really want consistently developed negatives to avoid having to adjust the enlarger color filtration and exposure time constantly. I know the 19 rolls developed in a few days are consistently developed because I can use the same enlarger settings from negative to negative and roll to roll, making adjustments only if there was some special lighting or exposure conditions.
As far as extending to more rolls, 20 rolls equals $1 per roll - what more do you want, why chance poor results, considering the costs of your camera, traveling to places to shoot, and film?
x-ray
Veteran
BLIX may have changed particularly between different makers over the years so my comment is a reference for researching the topic. Years ago I ran a lot of Kodak C-41 and E-6. In both I reused the bleach, now BLIX. BLeach had quite a bit of capacity so I used it several times but monitored my process with test strips and read them on a densitometer. I was running in a commercial rotary tube machine made by Colenta. BLeach / BLIX needs to be oxigenated to keep it from forming leuco-cyan dyes in the C-41 film. The prescribed method was to use an aquarium pump and air diffuser. Oxidation was critical for correct cyan due formation.
Something that happens using depleted or oxidized developer is called color crossover. If you run test strips and read on a densitometer crossover occurs when one color curve, say cyan, crosses over , say the yellow curve. It's not necessarily this combination but the result is a color shift that can't be corrected. It doesn't matter whether scanned or set printed you have colors that can't be corrected. This is something Ive seen quite a few times in sample images on RFF. Exhausted developer results in flat thin negatives with little to no shadow information resulting in blue muddy shadows.
Edit: I'm not sure if folks understand this. Oxidation of the developer occurs from exposure to air but the developing process itself results in a huge amount of oxidation even in the absence of air. The development of film is a RE/DOC reaction, reduction / oxidation reaction. It's an ion exchange betwee the silver halide and the developing agent in the process of reducing AgX to metallic silver. You can processs film in an inert Argon atmosphere and you'll still have oxidation. This oxidation results in the reduction of activity of the developer, thin muddy blue shadows and strange muddy colors in a flat neg.
Something that happens using depleted or oxidized developer is called color crossover. If you run test strips and read on a densitometer crossover occurs when one color curve, say cyan, crosses over , say the yellow curve. It's not necessarily this combination but the result is a color shift that can't be corrected. It doesn't matter whether scanned or set printed you have colors that can't be corrected. This is something Ive seen quite a few times in sample images on RFF. Exhausted developer results in flat thin negatives with little to no shadow information resulting in blue muddy shadows.
Edit: I'm not sure if folks understand this. Oxidation of the developer occurs from exposure to air but the developing process itself results in a huge amount of oxidation even in the absence of air. The development of film is a RE/DOC reaction, reduction / oxidation reaction. It's an ion exchange betwee the silver halide and the developing agent in the process of reducing AgX to metallic silver. You can processs film in an inert Argon atmosphere and you'll still have oxidation. This oxidation results in the reduction of activity of the developer, thin muddy blue shadows and strange muddy colors in a flat neg.
benlees
Well-known
Personally, I applaud those who stretch what "should" be done. Of course, I'm about to start developing some c41 and I want the chems to last as long as possible...
I'm all for reading the instructions...
I'm all for reading the instructions...
Ko.Fe.
Lenses 35/21 Gears 46/20
One year, 30+ films, in the fridge, not freezing. Toasted after getting it dirty with ECN2 film.
If you are printing in DR, follow the instruction. Something like 15 films. If LR, follow your scans.
If you are printing in DR, follow the instruction. Something like 15 films. If LR, follow your scans.
michaelwj
----------------
I just did my first batch with the unicolor kit. My big piece of advice is that the BLIX mixture outgassed as it works. I poured it in, put the lid on my paterson tank and after two inversions the pressure inside the tank almost blew it open. After that I poured it it, one inversion, quick vent, 5 inversions and vent again. I then left the lid off between inversion cycles (as in, put the lid on every minute for the 10 inversions). The speed of the initial reaction really caught me by surprise the first time, and I had read that it needed venting but didn't think it would be that fast.
Chris101
summicronia
I used plastic bottles for my unicolor kit. I squeezed the air out of them, and they lasted for many rolls. I quit using them when the negatives started showing any loss of density.*
*About a year over 16 rolls. But don't quote me.
*About a year over 16 rolls. But don't quote me.
dmr
Registered Abuser
A few related (and not so) comments ...
I regard this board and a few others to be excellent sources of true expertise, and I value it highly. From things as diverse as sticky shutters to chemical mixing, I've always had good responses to all serious questions (and even a few stupid ones) I've asked.
I do hear what you mean. On another system when I posted some initial queries about processing C41 and E6 I did get some good answers, but also a sprinkling of exactly what you stated, those who admitted they had never processed C41 but somehow felt the need to tell me how to do it.
I was able to find a can of that "Bloxygen" argon stuff. Next time I do a couple of rolls I plan on using that on all of the remaining chemicals. I thought of doing that proactively, but figured it's probably better to leave the bottles in the fridge as-is than to open them yet again for the sole purpose of spraying argon in them.
What confuses me the most, and is most difficult to understand, are the things that are totally contradictory! I think that all items were presented in good faith, but they are indeed confusing.
This (number of rolls you can do with consistent results) is one of them.
Another is temperature. On one hand we have a retired Kodak "Photo Engineer" on "another network" who says quite authoritatively that C41 was meant to be done at 100F (102?), period, no exceptions, and many others saying they have done it with good results with a lukewarm low 80sF range. The kit I have (Cinestill) has a time/temperature chart going down to the 70sF range.
Then there's the "Blix will last forever, just keep using it" and "Blix goes bad fast" dichotomy.
What I plan to do when I have a free afternoon is take three test rolls, all of the same subjects, identical exposure and such. Mixture of test charts and some real-world scenes. Then I plan to do one roll EXACTLY to official specs, temperature-wise, another doing my planned dilution for one-shot, and another at a reduced temperature and compare all of them carefully.
I regard this board and a few others to be excellent sources of true expertise, and I value it highly. From things as diverse as sticky shutters to chemical mixing, I've always had good responses to all serious questions (and even a few stupid ones)
I've asked.I do hear what you mean. On another system when I posted some initial queries about processing C41 and E6 I did get some good answers, but also a sprinkling of exactly what you stated, those who admitted they had never processed C41 but somehow felt the need to tell me how to do it.
I was able to find a can of that "Bloxygen" argon stuff. Next time I do a couple of rolls I plan on using that on all of the remaining chemicals. I thought of doing that proactively, but figured it's probably better to leave the bottles in the fridge as-is than to open them yet again for the sole purpose of spraying argon in them.
What confuses me the most, and is most difficult to understand, are the things that are totally contradictory! I think that all items were presented in good faith, but they are indeed confusing.
This (number of rolls you can do with consistent results) is one of them.
Another is temperature. On one hand we have a retired Kodak "Photo Engineer" on "another network" who says quite authoritatively that C41 was meant to be done at 100F (102?), period, no exceptions, and many others saying they have done it with good results with a lukewarm low 80sF range. The kit I have (Cinestill) has a time/temperature chart going down to the 70sF range.
Then there's the "Blix will last forever, just keep using it" and "Blix goes bad fast" dichotomy.
What I plan to do when I have a free afternoon is take three test rolls, all of the same subjects, identical exposure and such. Mixture of test charts and some real-world scenes. Then I plan to do one roll EXACTLY to official specs, temperature-wise, another doing my planned dilution for one-shot, and another at a reduced temperature and compare all of them carefully.