Catlabs C-41, Mixing, Jobo Thermometer location, epic fail

nbagno · Jan 10, 2014

Got my C-41 Kit (1L). Not an expert in all of this but I try to plow through it. Have a few questions.

1- I mixed up a 1L batch for use in my 470ml tank on my CPA-2. I round up to 500ml. The instructions say that I can reuse the developer up to three times by adding 00:15 to the processing times. So if my tank holds 2 rolls, my 500ml of developer can develop 6 rolls?
2- C-41 dev temp should be measured where? In the developer or at the thermometer holder in the top of the water bath?
3 - Yesterday after work (tired) once the developer cycle was done I reached past the bleach and put the fix in.. Dumped it back into the 1L container and put bleach in, then the fixer again. I think there was a wash in between the bleach and fix, going from memory. Is that a problem? No UFO's on the rolls so I wasn't that concerned that I screwed it up, other than the waist of time and money.

wildbill · Jan 10, 2014

1. yes
2. you want the chemicals to be the proper temp. and the water the drum is in to be very close to that. Make sure the bath is up as high as it will go to heat the chems, if not they'll always be slightly under the bath temp. add more water to the bath if needed after you put the chem bottles in.
3. it's a good idea to follow directions not much room for error.

bdial · Jan 10, 2014

You should measure the temperature of the developer.
Not sure about having the heat as high as it will go, but you will need the processor's heater set to a few degrees higher than the desired developer temperature. You'll need to experiment to find the right setting.

pbromaghin · Jan 10, 2014

I just did my first C-41 with the CatLabs 5L kit a couple weeks ago so I understand your nerves. I completely ruined one roll when the top popped off the tank from my sloppy handling.

To get the number of rolls you can process with 500 ml, I wouldn't go by how many your tank holds, but take the recommended number of rolls for the liter and divide by 2.

Put the thermometer in the chemicals.

Sad to say your bleach is probably ruined by the fix that remained in the tank when you backtracked. All is not lost, though because both bleach and fix are good for about double the capacity of the developer, so you still have enough good bleach to go with your developer. You'll just have extra fixer when you're done.

CatLABS · Jan 10, 2014

Measure the temp (38C) directly in the developer bottle. Watch out - the thermometer should be cleaned before every time you insert it in the bottle. A single drop of bleach will kill the developer. By the time the developer is at the correct temp, both the bleach and fix (if they were in the machine as long as the developer) will be close enough to temp, so there is no real need to measure them. You can be off by +/-5C on Bleach or fix.

A simple way to avoid that mistake is to leave an empty slot between each of the 3 process bottles. That way the fixer is all the way at the end. As pbromaghin said - your kit has about twice as much Bleach/fix capacity as developer so nothing is lost. Mix new batches and keep going.

pentaxuser · Jan 10, 2014

pbromaghin said:
I completely ruined one roll when the top popped off the tank from my sloppy handling.

Put the thermometer in the chemicals.

Your unfortunate experience has reminded me to say to the OP to be very careful about using the rotary processor at the stop-bath stage. I have never failed to get a gas build-up at this stage which blows the top cover off and spills the stop-bath. As this is only a very short stage I'd hand-invert the tank instead.

pentaxuser

nbagno · Jan 10, 2014

CatLABS said:
Measure the temp (38C) directly in the developer bottle. Watch out - the thermometer should be cleaned before every time you insert it in the bottle. A single drop of bleach will kill the developer. By the time the developer is at the correct temp, both the bleach and fix (if they were in the machine as long as the developer) will be close enough to temp, so there is no real need to measure them. You can be off by +/-5C on Bleach or fix.

A simple way to avoid that mistake is to leave an empty slot between each of the 3 process bottles. That way the fixer is all the way at the end. As pbromaghin said - your kit has about twice as much Bleach/fix capacity as developer so nothing is lost. Mix new batches and keep going.

I was keeping the final wash water in the last 3 slots. Is it okay to use the final wash at room temp? Ok garage temp which is about 60 degrees in sunny California :-D

nbagno · Jan 10, 2014

So the 5L kit says 60-80 rolls, I'll use 60 to be conservative (developer)

Check my math please:
5L = 60 rolls
1L = 12 rolls
.5L = 6 rolls
Correct?

adelorenzo · Jan 10, 2014

pentaxuser said:
Your unfortunate experience has reminded me to say to the OP to be very careful about using the rotary processor at the stop-bath stage. I have never failed to get a gas build-up at this stage which blows the top cover off and spills the stop-bath. As this is only a very short stage I'd hand-invert the tank instead.

Not sure what tank you are using but with the red rubber Jobo lids you can push them in when you put them on. When I'm doing blix stage and the lid pops out I grab the tank, remove it to release the rest of the pressure and then put it back on. It's working so far.

CatLABS · Jan 10, 2014

pentaxuser said:
Your unfortunate experience has reminded me to say to the OP to be very careful about using the rotary processor at the stop-bath stage. I have never failed to get a gas build-up at this stage which blows the top cover off and spills the stop-bath. As this is only a very short stage I'd hand-invert the tank instead.

pentaxuser

Not a problem when using a Jobo with a LIFT, as there is never any pressure buildup.

CatLABS · Jan 10, 2014

nbagno said:
So the 5L kit says 60-80 rolls, I'll use 60 to be conservative (developer)

Check my math please:
5L = 60 rolls
1L = 12 rolls
.5L = 6 rolls
Correct?

Yes.

As the rinse will be after the developer and bleach have completed their duty, the rinse water temp is not that crucial. Ideally it would be at process temp, but you can live with anything that is not super hot or super cold. You only need one rinse bottle (depending on the tank size but 2 reel tanks are usually in the 240-270ml range), so you can have still, a gap between the bottles.

Final wash off the machine with tap water warmed up to where you want it, or slightly longer at 60F.

CatLABS · Jan 10, 2014

adelorenzo said:
Not sure what tank you are using but with the red rubber Jobo lids you can push them in when you put them on. When I'm doing blix stage and the lid pops out I grab the tank, remove it to release the rest of the pressure and then put it back on. It's working so far.

+1 (when not using a lift)

wildbill · Jan 10, 2014

I meant the bath water level as high as you can go, not bath temp.

pbromaghin · Jan 11, 2014

nbagno said:
So the 5L kit says 60-80 rolls, I'll use 60 to be conservative (developer)

Check my math please:
5L = 60 rolls
1L = 12 rolls
.5L = 6 rolls
Correct?

My calculations are very different, but this is about what I come up with. My equipment is in quarts so I have a very different problem than you do.

Catlabs C-41, Mixing, Jobo Thermometer location, epic fail

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