C41 at home without a JOBO

Bormental · Jul 7, 2020

I am preparing for my first home-cooked batch of C-41. Unfortunately, I have no room for a JOBO processor, so I am going to use good old Paterson tanks and a temperature-controlled bath. To practice my temperature-maintaining skills, I started to use my usual B/W process as a playground, but with stricter control.

What I noticed is that the temperature of the developer changes by 0.5-1C when it is poured into the tank, due to tank+film native temperature being different (usually hotter than 21C due to summer weather). With C41 I would imagine temperature drop. Should I pre-soak the film with water at correct temp?

The second Q is about the lack of clarity regarding agitation. I've ran some searches and people have expressed preferences, which is strange... AFAIK C41 is not like B/W. Everything (time+temp) is standardized and this means there should be no room for "preferences". I expect my color chemicals to come with agitation instructions for small tanks (and a matching time) - is that true?

Thanks!

David Lyga · Jul 7, 2020

Start your development at 3 degrees higher Fahr or 2 degrees higher Celcius and agitate once upside down every thirty seconds and you will be in good shape. - David Lyga

Bormental · Jul 7, 2020

Thank you, David!

mohmad khatab · Jul 8, 2020

Bormental said:
I am preparing for my first home-cooked batch of C-41. Unfortunately, I have no room for a JOBO processor, so I am going to use good old Paterson tanks and a temperature-controlled bath. To practice my temperature-maintaining skills, I started to use my usual B/W process as a playground, but with stricter control.

What I noticed is that the temperature of the developer changes by 0.5-1C when it is poured into the tank, due to tank+film native temperature being different (usually hotter than 21C due to summer weather). With C41 I would imagine temperature drop. Should I pre-soak the film with water at correct temp?

The second Q is about the lack of clarity regarding agitation. I've ran some searches and people have expressed preferences, which is strange... AFAIK C41 is not like B/W. Everything (time+temp) is standardized and this means there should be no room for "preferences". I expect my color chemicals to come with agitation instructions for small tanks (and a matching time) - is that true?

Thanks!

Hi ,,
I have experience that I gained after suffering in this context.
I learned from the late Ron Mawry, a wonderful lesson.
First: The film must be soaked in warm water with a temperature of no less than 37 ° C.
- Patterson Tank hears that you insert a thermometer to dive into the tank in order to check the temperature of the water inside the tank, and when the temperature reaches 38 degrees, you dispose of the water and pour the developer into the tank instead of water ,,
Of course, it is assumed that the developer originally had his temperature measured before that step, and his temperature was checked accurately.
Therefore, I suspect that the optimum plan is to use 3 thermometers at the same time.
- Yes, maybe my words will get a lot of surprise and perhaps some irony, but it is the best plan to set the temperature with extreme accuracy.
- a thermometer placed in a water tank,
A thermometer that is placed in the developer package
A thermometer placed inside the warm water in the tank.
Trust me ,, you will get the best accuracy
Pouring and unloading the developer:
The developer must be placed in a large mouthed plastic container in order for the developer to be poured as quickly as possible. And do not run the watch until after the developer completes pouring to the last point and the entire amount of the developer becomes inside the tank.
- When the developer is also unloaded, you must pour the developer off five seconds before the standard time,
After emptying the tank from the developer, the distance between you and the water faucet must not exceed half a meter,
- Tap water should preferably be warm water, and it is preferable that the tap water temperature be the same as the process temperature 38 or slightly lower.
- It is preferable that time is not wasted after the tank is empty from the developer, and that the journey that the tank will take until the warm tap water is reached does not exceed five seconds.
These strange, strange and suspicious ideas are the result of a lot of pain and failure.
Thank God now the results are so wonderful.
One last tip
I hope you prepare your photochemistry with your hand from scratch.
Trust me, you will feel the unspeakable joy,
You live in San Francisco, and you can get access to chemical raw materials easily.

Bormental · Jul 8, 2020

Mohamad, awesome. Thanks.

koraks · Jul 8, 2020

Just put the tank with the film in it into the water bath and leave it there for 15 minutes or so. It'll come to temperature, reducing the issue.
A prebath can also work; it's recommended by some and discouraged by others, but I never noted any ill effects from it.

Agitation: you could try permanent agitation with the twizzle stick that comes with the Paterson while keeping the tank largely submerged. Some people believe that it gives uneven development, but I never observed this. I don't think a laminar flow (the likely cause of uneven development in this scenario) is actually possible to get when using the twizzle stick. If it fails, try intermittent agitation in the normal way every 20 or 30 seconds or so. Temperature may be more difficult to maintain in that scenario.

mshchem · Jul 8, 2020

I've got Jobo machines now, but I processed a lot of color film in a Paterson tank. I used a good German made aquarium heater to help steady the temperature. With C41 just prewarm your tank, I used to put the tank under my tee shirt and under my arm. That will warm it up, quick, then just float your bottles in the water bath any plastic bucket will do. Better to have the developer a bit warm as David suggests. Main thing is not to under develop . Keep it nice and warm, maybe go an extra 10-15 seconds in the developer, you can go a little over with negative film, E6 is a no no. I agitated per Kodak, for small tank 2 or 3 quick inversions (5 seconds total) every 30 seconds.

AgX · Jul 8, 2020

To sum up what has been said:

-) start with the processing bath at higher temperature, so that at average the temperage wiil be allright. Kodak once explained this method in their C41 amateur processing sheet
or
-) put the loaded tank together with the prepared baths into the tempering bath too.

Bormental · Jul 8, 2020

Or... I can heat up my apartment to 39C a few hours ahead of development! ;-)

AgX · Jul 8, 2020

That of course would be the foolproof method.

But for unknown reason I never saw it described in textbooks or manuals....

Ian Grant · Jul 8, 2020

I started with Pavelle color for prints and Ferrania for slides both processes were super critical when it came to temperature, +/- 0.5ºF in the day before accurate digital thermometers. E3/4 was a little easier and I never had issues using Paterson tanks, by the time C41 and later E6 came along only the first stage was really critical for temperature (and time) as the rest are to completion anyway.

It's quite easy to use a bowl of water as a tempering bath and with a little experience you soon realise that it's simple to keep the tank to 37ºC +/- 0.5º, experience and practice helps.

Ian

foc · Jul 8, 2020

Your developer is the most important chemical to have accurate temperature control. You have great advice above on how to achieve this.
Ideally, the rest of your chemicals should be the same but it's not as critical, a little variance in temperature won't do any harm.
Once I had a C41 processing machine that blew the bleach tank heater and it would be a few days before I would get a replacement. I was going to use a fish tank heater but didn't need it in the end as the dev tank and fix tank either side kept the bleach tank at 33C, ok 5C lower than it should be but it worked.(if bleach goes below 30C it can affect the total process) .

Donald Qualls · Jul 8, 2020

I use a sous vide cooker to heat my tempering bath, and when everything else is up to temp (starting with warm, but below dev temp, tap water, this can take as little as twenty minutes), I dip a tankful of the tempering bath to prewash the film. This quickly brings the tank and contents up to temperature, though if I was stingy with the water level in the bath it may result in the sous vide shutting off due to low water level. Doesn't matter; I can restart it when the tank is standing in the bath, and if needed, again when I pour the wash back into the bath.

Prewarming the empty tank raises the issue of flotation. I don't keep bricks or weight plates in my darkroom...

AgX · Jul 8, 2020

But I guess everyone finds something apt in house to use as a weight. Ideal of course would be something like a ring to be put around the tank opening. One might fill a piece of tube with sand close the ends with putty, wind the tube and fix it to itself with binders.

Rafael Saffirio · Jul 8, 2020

I pre heat the developer and blix in the microwave, to around 40 C after I pour it in the paterson tank it cools to around 38 the developing time is so short that it just cools something like 0.5C. I do a prewash at 40C for 1 minutes before the developer.

AndyH · Jul 10, 2020

I will put in a plug for the sous vide method. I bought a "Kitchen Boss" model, new but open box, on eBay for 39.95 plus $8 shipping. There are many available new for under $70. I've not had time for much developing during this pandemic, but I tested it with my bottled developer and blix using a plastic dishpan as a temperature bath. I put two one-litre bottles and stainless steel tank filled with water in the bath, and monitored temperature for longer than the development and fixing time needed. It kept everything within one half degree Fahrenheit for the entire time. Best fifty five bucks (including the dishpan) I've spent on photography in a while; I can't wait for things to lighten up a little so I can do some real negatives.

As an added benefit, you can cook a steak to your ideal temperature and keep it from overcooking!

Andy

MattKing · Jul 10, 2020

For those using a sous vide cooker to control temperatures, are any of you using a hard sided cooler to hold the water? Insulation is your friend when it comes to temperature maintenance, and having a lid available during warm-up would probably help too.

Donald Qualls · Jul 10, 2020

My sous vide, at least ($32 plus shipping on eBay), has a pretty limited opening on the mounting clip. It just barely fits over the rim of the tub I'm using (which was an organizer/storage tub I got at Lowe's for $7); if the rim weren't slightly flexible, it wouldn't go on or come off.

The manufacturer claims the thermistor temperature sensor in the sous vide is more accurate than any common thermometer, and the cooker keeps my bath dead on (both by its own display and checked against my darkroom bimetal thermometer) for as long as its timer runs (it was set to 8:00:00 when I got it, I've somehow changed it to 7:30:00, but that's much more time than I'll ever need, since the timer doesn't even start until it reaches set temperature). I've used it at 75F for Df96 monobath (in a 68F room), as well as 102F for Cinestill Cs41. I don't bother warming my other black and white developers -- 4% time per degree F (minimum 60F for hydroquinone) has served me well, and my darkroom runs pretty close to 68F anyway with the central air.

mshchem · Jul 10, 2020

This looks kinda neat. For preheating bottles for E6, one of these would be nice. Maybe not wi-fi. You could fire it up on the drive home from work.

mshchem · Jul 10, 2020

Donald Qualls said:
My sous vide, at least ($32 plus shipping on eBay), has a pretty limited opening on the mounting clip. It just barely fits over the rim of the tub I'm using (which was an organizer/storage tub I got at Lowe's for $7); if the rim weren't slightly flexible, it wouldn't go on or come off.

The manufacturer claims the thermistor temperature sensor in the sous vide is more accurate than any common thermometer, and the cooker keeps my bath dead on (both by its own display and checked against my darkroom bimetal thermometer) for as long as its timer runs (it was set to 8:00:00 when I got it, I've somehow changed it to 7:30:00, but that's much more time than I'll ever need, since the timer doesn't even start until it reaches set temperature). I've used it at 75F for Df96 monobath (in a 68F room), as well as 102F for Cinestill Cs41. I don't bother warming my other black and white developers -- 4% time per degree F (minimum 60F for hydroquinone) has served me well, and my darkroom runs pretty close to 68F anyway with the central air.

As long as there's adequate circulation these things should be very capable. 1100W heater probably works best with a large volume of water. I have a circulator for a big Arkay water bath, it has a LED readout, but there's two analog dials for adjusting temperature, course and fine. It's amazingly steady.

I like the idea of a insulated plastic cooler, make a cover that would hold your tank for pre-heating.

AgX · Jul 10, 2020

Donald Qualls said:
The manufacturer claims the thermistor temperature sensor in the sous vide is more accurate than any common thermometer, ....

The best digital lab thermometer for common temperatures I know has the same resolution and accuracy as a fluid-stem lab precision-thermometer. of same range. (Though this may not be the best comparison in regard to a plain sensor.)

MattKing · Jul 10, 2020

Donald Qualls said:
My sous vide, at least ($32 plus shipping on eBay), has a pretty limited opening on the mounting clip. It just barely fits over the rim of the tub I'm using (which was an organizer/storage tub I got at Lowe's for $7); if the rim weren't slightly flexible, it wouldn't go on or come off.

I bet you can rig up something that is easier to clip to.
And just think how handy that the drain valve at the bottom of some of those coolers would be!

AgX · Jul 10, 2020

MattKing said:
I bet you can rig up something that is easier to clip to.

Or alternatively remount the clip at the heater at larger distance to the body.

Donald Qualls · Jul 11, 2020

MattKing said:
I bet you can rig up something that is easier to clip to.
And just think how handy that the drain valve at the bottom of some of those coolers would be!

Oh, yes. The other big reason not to use a cooler is counter space. My darkroom counter is only three feet long and about 30 inches front to back, including the backsplash. I have a grid that goes into the sink and will hold something the size of my tub, but it's plastic and I'm not sure I'd trust it for significantly more water than the five gallons my tub will hold without getting too deep for bottles and tank, not to mention it's difficult to pour anything into the sink when the grid is on it and something heavy on the grid.

Yes, I could probably fabricate something to clip to, but the clip does go over the tub rim, just requires a little care attaching and removing.

As things stand, I dip enough water out of the tub to lighten it so I can then lift it and pour the remainder into the laundry tub sink that serves my darkroom.

The other limitation is that if the water bath is too deep, the bottles float around. This is the kind of randomness that can lead to pouring the chemicals in the wrong order, which I'd very much prefer not to do.

AgX said:
Or alternatively remount the clip at the heater at larger distance to the body.

Modern small appliances like this one are designed to keep people from modifying them ("tampering") without just breaking them and rendering them unusable. This kind of design has been raised to a fine art in the case of electrical appliances intended for use around water -- and since it works well the way I'm using it, I'm very much not inclined to try to figure out what glue it would need, and then take a hacksaw to the plastic and reglue it with a spacer (which would eliminate the ability to clip on thinner material). Modifying the bath container would be much more practical, but see above for my work space limitations.

AgX · Jul 11, 2020

Yes, you are right . More and more casings are just clipped together and unlikely to be got open again wiithout spoiling the casinfg or even breaking the clips-

(I am from the slit-screw generation...)

C41 at home without a JOBO

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C41 at home without a JOBO

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