Considering doing c41 at home

Steven Lee · May 31, 2023

@Radost I also did a bunch of tests comparing temperature drop between Jobo and Paterson tanks, and within 3:15 minutes I found zero difference between the two: they lose only about 1F during this short time, and another 1F is lost during pouring into a pre-heated tank (depends on the ambient temperature of course).

Basically it means that Cinestill instructions of recommending heating the developer to 102F are spot on. One does not need a water bath or sous vide to develop C41 at home, as long as a tank is full (inversion agitation volume for JOBO).

Water bath is needed for rotation.

Radost · May 31, 2023

Steven Lee said:
@Radost I also did a bunch of tests comparing temperature drop between Jobo and Paterson tanks, and within 3:15 minutes I found zero difference between the two: they lose only about 1F during this short time, and another 1F is lost during pouring into a pre-heated tank (depends on the ambient temperature of course).

Basically it means that Cinestill instructions of recommending heating the developer to 102F are spot on. One does not need a water bath or sous vide to develop C41 at home, as long as a tank is full (inversion agitation volume for JOBO).

Water bath is needed for rotation.

I put 100F dev in to the tank rolling in 102F bath

Xylo · May 31, 2023

My darkroom being just next to the hot water heater, I just set the tank as close as possible to the target temperature and leave it like that.
Also, unless you plan on doing RA-4 printing, the color drift associated with developing at the wrong temperature is not hard to correct. I know a guy who did room temperature C-41 and his results were more than acceptable.

He had hand made a chart for calculating the times for room temperature which he gave me, so I did a non-linear regression on it and put it in a spreadsheet. So far, the results I get are good enough for me.
If anybody wants it, I can post it here. It does require a bit of adjustment according to the kit you use (change the offset), but the curve remains the same.

Steven Lee · May 31, 2023

Xylo said:
My darkroom being just next to the hot water heater, I just set the tank as close as possible to the target temperature and leave it like that.
Also, unless you plan on doing RA-4 printing, the color drift associated with developing at the wrong temperature is not hard to correct. I know a guy who did room temperature C-41 and his results were more than acceptable.

Great point which is rarely mentioned. There's one caveat though: this depends on a film somehow. Something wonky happens with Fuji Superia 400 if the temperature is off, specifically on the green/magenta axis, that's not easy to correct. Hard to describe. Meanwhile the C-200 is the opposite: very easy to work with. On the Kodak side, Portras are easier to color correct than Ektar, while the Ultramax is a nightmare. Again, this is only when temperature is not perfect, or when a developer is reused (as all kits require you to do). Things are much easier when developing in freshly mixed Flexicolor precisely at 100F.

Radost · May 31, 2023

Steven Lee said:
Things are much easier when developing in freshly mixed Flexicolor precisely at 100F.

Exactly the same experience.

Xylo · Jun 1, 2023

Steven Lee said:
There's one caveat though: this depends on a film somehow.

That's why I only use cheap expired consumer grade film
I figure that it has to be tougher and less finicky than pro grade film.
And besides, with it being expired, I'll never be able to notice if my processing is slightly off

Steven Lee · Jun 1, 2023

@Xylo I hear you! I suspect this is subjective though. Imperfect processing and scanning lead to color imbalance, but those imperfections can be pleasing. And we all have our own definitions of pleasing. It just so happens that my eyes are sensitive to green/magenta balance. Even minor variations there ruin the skies, skintone and vegetation for me.

BTW the pro-grade films aren't finicky at all. One of the reasons I do not shoot much Portra 400 is because it's too perfect: when I put an effort into color inverting Portra 400 it looks boringly accurate. Its medium format scans look exactly like my digital photos. From the engineering perspective that's quite an compliment, but that's not what I want. Fuji C200 and Kodak Gold 200 are perfect in that regard. Easy to color balance, not sensitive to development, yet they have that intrinsic film character.

Xylo · Jun 2, 2023

Steven Lee said:
One of the reasons I do not shoot much Portra 400 is because it's too perfect

In my case it's mostly because I can't afford the stuff and I have a freezer full of film I got when the local grocery store minilabs were closing in my area. Best I got was an 8 pack of Gold 200 for 1$... lets just say I emptied their liquidation bin at that price.

Radost · Jun 2, 2023

Steven Lee said:
@Radost I also did a bunch of tests comparing temperature drop between Jobo and Paterson tanks, and within 3:15 minutes I found zero difference between the two: they lose only about 1F during this short time, and another 1F is lost during pouring into a pre-heated tank (depends on the ambient temperature of course).

Basically it means that Cinestill instructions of recommending heating the developer to 102F are spot on. One does not need a water bath or sous vide to develop C41 at home, as long as a tank is full (inversion agitation volume for JOBO).

Water bath is needed for rotation.

Temperature drop is higher in my tests. But mainly heating Takes longer. Even not heating the Paterson lid gives higher drop.

Sirius Glass · Jun 2, 2023

Steven Lee said:
@Xylo I hear you! I suspect this is subjective though. Imperfect processing and scanning lead to color imbalance, but those imperfections can be pleasing. And we all have our own definitions of pleasing. It just so happens that my eyes are sensitive to green/magenta balance. Even minor variations there ruin the skies, skintone and vegetation for me.

BTW the pro-grade films aren't finicky at all. One of the reasons I do not shoot much Portra 400 is because it's too perfect: when I put an effort into color inverting Portra 400 it looks boringly accurate. Its medium format scans look exactly like my digital photos. From the engineering perspective that's quite an compliment, but that's not what I want. Fuji C200 and Kodak Gold 200 are perfect in that regard. Easy to color balance, not sensitive to development, yet they have that intrinsic film character.

I am quite the opposite. I like the film to work correctly and to record the colors at the best to its ability.

Xylo · Jun 2, 2023

Over the years I've read about a couple of techniques for temperature control.
The first involves measuring the temperature before and after development and calculating the average drop in the equation.
The second involves making the loaded tank float like a log in a water bath. When you need to agitate, you simply turn it on it's side, give it a few spins and then set it back on the bottom for the timeout period.

Considering doing c41 at home

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