C-41 +1 in Jobo 1520

Wayne · Sep 25, 2021

I'm going to do some C-41 for the first time in years, I've only dabbled in it once or twice and this will be my first serious effort. I will be using a Jobo 1520 to develop 2 rolls of 120 each time, and I have a Phototherm 14 temperature control bath. I'll be using Unicolor chems. I think I'll have to use about 500 ml to keep the tank from floating, though only 240 ml is required. But if I develop 2 more rolls in that 500 ml the next day, it should still be good right?

My plan is 4:00 for plus one development (3:30 is normal with the Unicolor kit). I'd rather not do inversion agitation so my main question is about doing rotational agitation and by that I mean twisty-turny agitation, not rolling. I'm not sure what the equivalent is to "4 inversions every 30 seconds". Has anyone worked that out?

koraks · Sep 25, 2021

Old Gregg said:
it's pretty much a continuous agitation process.

That's it.

Wayne said:
But if I develop 2 more rolls in that 500 ml the next day, it should still be good right?

Probably, yeah, sort of. I don't like reusing C41 developer without replenishment - in fact, I don't like reusing it at all. I much prefer one shot. It's relatively cheap anyway. Why risk it?

pentaxuser · Sep 25, 2021

Wayne My Jobo 1520 tank requires only 250 ml for rotational agitation but this means in a constant horizontal position. If twisty-turny means the tank is always horizontal then fine but even if the tank rises out of the horizontal for any time at all then 250 ml may not cover the whole film all of the time.

I suppose that if it is out of the horizontal for only a second or so then the developer remaining on the film will continue to do its job but it would have to be raised for very short periods only to avoid any chance of developer starvation in my opinion.

I'd be tempted to roll it back and forth along a top with the lid sticking over the edge so it was the equivalent of rotational agitation

If you do use 250ml and the twisty-turny agitation let us know how it goes. If everything goes well then let us know much out of horizontal the tank was and for how long.

I am all for saving developer and if twisty-turny creates no problems then this may be something others might want to try

Thanks

pentaxuser

Wayne · Sep 25, 2021

pentaxuser said:
Wayne My Jobo 1520 tank requires only 250 ml for rotational agitation but this means in a constant horizontal position. If twisty-turny means the tank is always horizontal then fine but even if the tank rises out of the horizontal for any time at all then 250 ml may not cover the whole film all of the time.

I suppose that if it is out of the horizontal for only a second or so then the developer remaining on the film will continue to do its job but it would have to be raised for very short periods only to avoid any chance of developer starvation in my opinion.

I'd be tempted to roll it back and forth along a top with the lid sticking over the edge so it was the equivalent of rotational agitation

If you do use 250ml and the twisty-turny agitation let us know how it goes. If everything goes well then let us know much out of horizontal the tank was and for how long.

I am all for saving developer and if twisty-turny creates no problems then this may be something others might want to try

Thanks

pentaxuser

Your talk of horizontal is a bit confusing. Horizontal would be like a drum on a roller. I'm talking about using it upright, vertical, like a yankee tank and rotating/twirling the tank in place like I've done for black and white for decades. You shoudln't need an agitator doohickey. I won't use 250 ml because then I'd have to hold it down constantly because the water bath requires about 4" of water to work. If it slips, then I've got a tank floating like a bobber.

koraks said:
I much prefer one shot. It's relatively cheap anyway. Why risk it?

Maybe you are using Flexicolor but Unicolor is not cheap. I'm only using half the nominal capacity developing 2 rolls in 500 ml. I would only get 8 rolls of 120 instead of 16 rolls out of the 2 liters that I spent 50-some dollars on, which would be insanely expensive. I'm pretty sure reuse the next day would not show noticeable deterioration, but a few days most likely would. Its reuse, true, but its still well within capacity.

koraks · Sep 26, 2021

Wayne said:
Maybe you are using Flexicolor

No, Fuji.

Wayne said:
Unicolor is not cheap

So buy cheaper stuff. Why go for expensive if cheap is available, and is just as good if not better in quality?

Wayne said:
I'm only using half the nominal capacity developing 2 rolls in 500 ml.

No, you're adding development byproducts to 500ml of developer, effectively seasoning it, which will affect in particular the development speed of the different layers compared to each other. In other words, you're affecting color balance. Maybe just a little - maybe enough to be problematic. Why risk it?

Wayne said:
its still well within capacity.

Developer, and in particular color developer, does not work in a binary way: it's either good or it's not good. If you want to look at it that way, it's only 'good' if fresh or correctly replenished - in all other scenarios it's not good. The whole reuse-without-replenishment philosophy relies on accepting certain levels of 'not good'. Again - why risk it...

Tom Kershaw · Sep 26, 2021

koraks said:
The whole reuse-without-replenishment philosophy relies on accepting certain levels of 'not good'. Again - why risk it...

As I've mentioned a couple of times here in the past, last year I experimented with replenishment of C-41 developer - in a Jobo - with the result that the developer solution "falls over" after a while, even with generous replenishment. From a quick evaluation negative density looks fine but the colour quality and consistency drops off. I now use 1000ml one-shot with consistent results.

koraks · Sep 26, 2021

I'm not surprised, Tom. I wouldn't expect a small volume of <5 liters of relatively infrequently replenished developer to remain stable over the long term. A few weeks, tops. Replenishment has always been targeted at volumes of at least dozens of rolls per week, with the accompanying turnaround tank turnaround times remaining fairly short.

Auer · Sep 26, 2021

I use a 1520 standing up in a tub with a circulating heater.
With 485ml of developer in it I place it on top of an inverted pyrex container and have the water up to the red lock ring.
I put it in a corner of the tub for a slight lean and it stays put. I use Cinestill chemicals and do 4 inversions (out of the hot water tub) every 30 sec.
I re-use for about 16 rolls or so, so I add time per roll as I go.
I also have used a Lab-Box successfully for C-41 and sometimes still do. I have it on a heat pad as I cant immerse it.

Edit: I have the temp set to 104 for C-41 and 108 for ECN-2

pentaxuser · Sep 26, 2021

Wayne said:
I think I'll have to use about 500 ml to keep the tank from floating, though only 240 ml is required.

Thanks for the reply. I was concerned that maybe when you mentioned on 250ml being required that you might be tempted to try it. After all it would be possible for instance to hold the tank down so it didn't float in the bath. All that I was getting at was that 250ml is not all that is required except for horizontal rotation. 500ml may be what is required to hold the tank down but even if it wasn't required for that purpose it would still be needed for any form of inversion agitation.

pentaxuser

Wayne · Sep 26, 2021

koraks said:
No, Fuji.

So buy cheaper stuff. Why go for expensive if cheap is available, and is just as good if not better in quality?

Um, don't know how much attention you've been paying but there's been a shortage of many things including C41 chems. Plus Fuji is almost exactly the same price as unicolor, and its backordered till 2022 at Freestyle. I couldn't even find 1 liter Unicolor, which is technically all I need for the film I will be developing in the near future. It simply wasn't available so I had to buy 2 liters.

We're veering a bit here. I already have what I have, and what I have is what I will use. My main question is about agitation.

No, you're adding development byproducts to 500ml of developer, effectively seasoning it, which will affect in particular the development speed of the different layers compared to each other. In other words, you're affecting color balance. Maybe just a little - maybe enough to be problematic. Why risk it?

I'm no chemist but after 2 minutes of developing a roll a C41 you are developing in byproducts too. At the end of developing 2 rolls, you'll have twice as many byproducts as I will be starting with. I'm not saying you are wrong, just saying compromises sometimes have to be made. I'm not going to use 8 dollars worth of chemicals for each roll. If I have a higher volume of film to develop in the future I would buy Kodak but I don't have the volume to justify it. I'm generally not a "reuse" guy with color so I don't disagree with what you're saying.

Auer · Sep 26, 2021

Wayne said:
Developer, and in particular color developer, does not work in a binary way: it's either good or it's not good. If you want to look at it that way, it's only 'good' if fresh or correctly replenished - in all other scenarios it's not good. The whole reuse-without-replenishment philosophy relies on accepting certain levels of 'not good'. Again - why risk it...

Man, I must have low standards....

Wayne · Sep 26, 2021

pentaxuser said:
Thanks for the reply. I was concerned that maybe when you mentioned on 250ml being required that you might be tempted to try it. After all it would be possible for instance to hold the tank down so it didn't float in the bath. All that I was getting at was that 250ml is not all that is required except for horizontal rotation. 500ml may be what is required to hold the tank down but even if it wasn't required for that purpose it would still be needed for any form of inversion agitation.

pentaxuser

Thanks. I don't think I knew that.

koraks · Sep 27, 2021

Wayne said:
I'm no chemist but after 2 minutes of developing a roll a C41 you are developing in byproducts too.

Obviously. Which is something the manufacturer of the chemistry knows, and accounts for. This is also part of the reason why some argue that volumes as low as 150ml/roll (e.g. single 135 roll in Jobo 1510, continuous rotation) are NOT a valid option.

Wayne said:
We're veering a bit here. I already have what I have, and what I have is what I will use. My main question is about agitation.

IIRC you asked two questions: how to agitate, and is it OK to reuse 500ml of developer that's already been used for 2 rolls? You're apparently looking for a soothing answer on the second part to put your mind at ease. So have it: it'll be all fine.
Agitation: continuous. If that's not what you want to hear: anything you like, as long as it's enough. I'd say "agitate as frequently as feasible."

Tom Kershaw · Sep 27, 2021

koraks said:
This is also part of the reason why some argue that volumes as low as 150ml/roll (e.g. single 135 roll in Jobo 1510, continuous rotation) are NOT a valid option.

I stick to 1 roll of 120 per 250ml of developer approximately. There seems to be a lot of misinformation online about massively over using the C-41 developer (which is inexpensive) compared to time, resources, and film... I suspect part of this is down to promotion of the kits that are very expensive if not over-used. In my experience the bleach can be replenished extensively.

koraks · Sep 27, 2021

Tom Kershaw said:
I stick to 1 roll of 120 per 250ml of developer approximately.

That's probably a safe limit. The problem is really IMO in the conflicting and/or incomplete information we are provided on C41 developers. Either it's lab chemistry for which datasheets are available that outline the replenishment rates, from which you might deduce minimum required volumes, if not for the fact that these datasheets nearly never give guidelines for small tanks and always rely on the assumption of minilabs to dip & dunk systems. So the guidelines for replenishment are problematic to translate into guidelines for small tank processing. On the other hand there are consumer kits aimed specifically at small tank use, but these often come with overly optimistic volume-per-roll specifications - sometimes with very suspicious instructions ('for roll 2 & 3, add x% to development time') that can only point towards a compromised approach to C41 processing. In the end, the fundamental problem is that C41 developer was never made specifically to work with small tanks. It does so, but the boundaries within it does so well (i.e. within spec) are pretty much unspecified, at least for most brands and types of chemistry.

Auer · Sep 27, 2021

Let me stir the pot, from Cinestill:
https://cdn.shopify.com/s/files/1/0...nstructions_Complete.pdf?14374404616962145803

One is always concerned about chemistry life and capacity, quality of results and economy when processing
multiple rolls in a batch of chemistry. From the user’s viewpoint it may seem that chemistry manufacturers
are somewhat arbitrary about the number of films which can be processed before the chemistry must be discarded.

This stems from the manufacturer not knowing - only guessing - four essential things: how many films
will be processed in freshly mixed chemistry; in what manner and how long will the chemistry be stored before
processing again; what contaminants have entered the system from either the water supply or from unintentional
chemical intermixing; and how far can the results deviate from ideal before the user deems them unacceptable.

All developers start on an inexorable downhill exhaustion path the moment they are mixed, and
exhaust faster in the presence of air, contaminants and high temperature, and suffer superimposed stepwise
exhaustion with each use. We can offer some observations on extended chemical capacity:

• If you accept the role as the final arbiter of acceptable results it is easily possible to process 25%, 50%, or
even more rolls of film than those listed in the capacity charts above by following the instructions below for
“Chemical Reuse - Processing with Weakened Developer Solution”, so long as all processing takes place within
or even more rolls of film than those listed in the capacity charts above by following the instructions below for
“Chemical Reuse - Processing with Weakened Developer Solution”, so long as all processing takes place within
a few days after mixing the chemicals. There is only one rule in this exercise: process film until you no longer
like the results. The safeguard in this procedure is that results generally will not plummet precipitously from
“good” to “bad”, but will change gradually.

• If you take full responsibility for quality of results, it is possible to process more film over a much longer
time span. This procedure is somewhat risky unless you process some film every day or so to monitor chemistry
performance. Otherwise, partially used working solutions left untouched for a week or more might have
changed so significantly that you would suffer a dramatic decline in results. If you choose to operate under
these conditions, our best advice would be to process a small piece of test film, and on the basis of these
results, decide whether or not to commit valuable pictures to the chemistry

Auer · Sep 27, 2021

Part 2:

Chemical Reuse - Processing with Weakened Developer Solution

Using a volume of chemicals once will not destroy its ability to develop film. However, extra time must
be added to the processing to compensate for the weakened developer. Whenever reusing
developer, combine all u sed developer with u nused developer to make 1000ml of
Weakened Developer Solution and add 2% to the recommended development time for each
135/120 roll, 8x10 sheet and every four sheets of 4x5 previously processed.

For example, you just developed four rolls of film at 102ºF. You have several more rolls to process. To
process the next four rolls at 102ºF, combine used chemicals with unused chemicals to make
1000ml, multiply 3.5 (the development time at 102ºF) by 1.08 (8% increase). 3.5 x 1.08 = 3.78, so
you process the next four rolls at 102ºF for 3.75 minutes. The time for the next rolls used in the same
1000ml remixed developer is calculated in a similar manner, except the recommended development
time must be increased by 16% (2% for each roll previ ously processed). 3.5 x 1.16 = 4.06 or 4
minutes.

The same is true when mixing we akened developer solutions in 500ml and 2 Lite rs
volumes, except development time increase will differ. Weakened Developer Solution
instructions for 500ml, 1000ml, and 2 Lit ers mixtures are listed below.

500ML: Combine all u sed developer with u nused developer to make 500ml We akened
Developer Solution. Increase recommended development time by 4% for e ach roll/8x10
sheet/4x5(4) sheets previously processed.

1000ML: Combine all u sed developer with u nused developer to make 1000ml We akened
Developer Solution. Increase recommended development time by 2% for e ach roll/8x10
sheet/4x5(4) sheets previously processed.

2 LITERS: Combine all u sed developer with u nused developer to make 2 Lit ers Weakened
Developer Solution. Increase recommended development time by 1% for e ach roll/8x10
sheet/4x5(4) sheets previously processed.

Use the above formula for the Developer ONLY. Optimal results are obtained when chemicals are used only once. See “More Chemistry Capacity” section above for details. Mixing weakened developer solution is not recommend for push processing and is less effective at lower processing temperatures. Reusing the Blix does not affect the processing time.

koraks · Sep 27, 2021

Auer said:
Using a volume of chemicals once will not destroy its ability to develop film. However, extra time must
be added to the processing to compensate for the weakened developer.

This is a simplification that does not account entirely for the influence of halides leaching from previously developed film into the developer (as well as more minor effects such as pH drift). While the overall gamma can be kept within the same region as the first film that's developed, it becomes increasingly difficult to maintain tracking between the different emulsion layers. The matter is more complex than 'developer activity'. Why CineStill does not account for this, I don't know. Probably not to confuse consumers. Personally, I'd rather be confused than incompletely informed.

Donald Qualls · Sep 27, 2021

I've used swizzle stick agitation in my Paterson tanks since I started doing C-41 again in mid-2020 (replenished Flexicolor, hence swizzle stick to minimize air mixing into the color developer). I've never seen problems with it. I do the equivalent agitation by time -- 5-6 inversions in 10 seconds seems to be near enough to working nice long swizzle stick turns for the same time, which in my experience comes to about a dozen turn-and-reverse cycles per agitation interval.

I don't think I've seen swizzle sticks for Jobo reels, however, so I presume you're doing something like picking up the tank and swirling it -- which seems to me much more prone to show flow marks and unevenness. Not sure, though, haven't tried it.

Wayne · Sep 27, 2021

Auer said:
Let me stir the pot, from Cinestill:
https://cdn.shopify.com/s/files/1/0...nstructions_Complete.pdf?14374404616962145803

One is always concerned about chemistry life and capacity, quality of results and economy when processing
multiple rolls in a batch of chemistry. From the user’s viewpoint it may seem that chemistry manufacturers
are somewhat arbitrary about the number of films which can be processed before the chemistry must be discarded.

This stems from the manufacturer not knowing - only guessing - four essential things: how many films
will be processed in freshly mixed chemistry; in what manner and how long will the chemistry be stored before
processing again; what contaminants have entered the system from either the water supply or from unintentional
chemical intermixing; and how far can the results deviate from ideal before the user deems them unacceptable.

All developers start on an inexorable downhill exhaustion path the moment they are mixed, and
exhaust faster in the presence of air, contaminants and high temperature, and suffer superimposed stepwise
exhaustion with each use. We can offer some observations on extended chemical capacity:

• If you accept the role as the final arbiter of acceptable results it is easily possible to process 25%, 50%, or
even more rolls of film than those listed in the capacity charts above by following the instructions below for
“Chemical Reuse - Processing with Weakened Developer Solution”, so long as all processing takes place within
or even more rolls of film than those listed in the capacity charts above by following the instructions below for
“Chemical Reuse - Processing with Weakened Developer Solution”, so long as all processing takes place within
a few days after mixing the chemicals. There is only one rule in this exercise: process film until you no longer
like the results. The safeguard in this procedure is that results generally will not plummet precipitously from
“good” to “bad”, but will change gradually.

• If you take full responsibility for quality of results, it is possible to process more film over a much longer
time span. This procedure is somewhat risky unless you process some film every day or so to monitor chemistry
performance. Otherwise, partially used working solutions left untouched for a week or more might have
changed so significantly that you would suffer a dramatic decline in results. If you choose to operate under
these conditions, our best advice would be to process a small piece of test film, and on the basis of these
results, decide whether or not to commit valuable pictures to the chemistry

I guess Cinestill = Unicolor because that is found word for word in the Unicolor instructions

Wayne · Sep 27, 2021

koraks said:
That's probably a safe limit. .

That's not a random number, its the manufacturer's stated limit, for single use. EDIT: NVM, no its not. That's half the stated capacity. At roughly 30 bucks per liter that's 7.50 per roll. A lab could do it for less than that. Seems like a waste of time and money.

Auer · Sep 27, 2021

Donald Qualls said:
I've used swizzle stick agitation in my Paterson tanks since I started doing C-41 again in mid-2020 (replenished Flexicolor, hence swizzle stick to minimize air mixing into the color developer). I've never seen problems with it. I do the equivalent agitation by time -- 5-6 inversions in 10 seconds seems to be near enough to working nice long swizzle stick turns for the same time, which in my experience comes to about a dozen turn-and-reverse cycles per agitation interval.

I don't think I've seen swizzle sticks for Jobo reels, however, so I presume you're doing something like picking up the tank and swirling it -- which seems to me much more prone to show flow marks and unevenness. Not sure, though, haven't tried it.

I just inverse my jobo every 30 seconds 4 times, about 10 seconds worth.
Can't say I ever noticed any flow marks.

Wayne · Sep 27, 2021

koraks said:
Agitation: continuous. If that's not what you want to hear: anything you like, as long as it's enough. I'd say "agitate as frequently as feasible."

Instructions state 4 inversions every 30 seconds. How does that equate to continuous?

Bronson Dugnutt · Sep 27, 2021

Whatever you do, don't accidentally (or on purpose) run Gold 200 through an E-6 process.

The horror...

pentaxuser · Sep 27, 2021

Bronson Dugnutt said:
Whatever you do, don't accidentally (or on purpose) run Gold 200 through an E-6 process.

View attachment 286413

The horror...

That pic in its own way looks pretty good to me. I can see it appealing to the new breed of colour film folk, a lot of whom seem to think of reporting Portra 400 to the appropriate authorities because it has been starved of colour

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