DIY C41 tempering bath

[shawn]

I built a C41 tempering bath out of a Finnex 300w aquarium heater. Stock the controller won't get high enough for C41. To modify the heater controller one resistor needs to be changed to alter the signal from the temperature sensor. Now if it is set to "90 degrees" the controller keeps the water temp at a very steady 104 degrees.

I just fill the tub with hot water, plug the heater in and let my chemicals heat up. As the water cools down the heater will maintain 104 degrees very well. By the time I am done with any B&W film the chemicals are ready to go for color. Just went through 5 hours of film processing and never had to touch the chemical temperature at all. I had a small pump to circulate the water but it wasn't working today and turns out it wasn't needed anyway.

Unfortunately, this mod prevents the heater from turning down enough for B&W. I find it unneeded for B&W anyway as I use one shot HC110 which is easy to get at the right temperature.

Shawn

 

[wjlapier]

Yep. I need to figure out a way where I'm not running hot water to bring up the temps of the chems.

Now the kids are back in school I can get started on my huge backlog of c41 film.

 

[splitimageview]

I bought a thermostatically controlled industrial water bath on ebay for $50. Otherwise your heater hack is a great idea!

 

[shawn]

Yep. I need to figure out a way where I'm not running hot water to bring up the temps of the chems.

Now the kids are back in school I can get started on my huge backlog of c41 film.

This works well. The heater is about $40 on ebay and they also have 100 and 200w versions of it.

Shawn

 

[wjlapier]

Did you change the resistor yourself? Is this something someone can easily do?

I've seen the water bath splitimageview mentioned.

 

[brbo]

What's a 104F tempering bath good for?

 

[shawn]

Did you change the resistor yourself? Is this something someone can easily do?

I've seen the water bath splitimageview mentioned.

Yes, I changed it. Easy to change if one can solder, it was a through hole component. I'll grab a picture of the change.

Shawn

 

[shawn]

What's a 104F tempering bath good for?

Rotary processing C41. The tempering bath isn't fixed at 104 degrees you can adjust it. The controller has a range from "67-93" degrees. The modification alters the signal from the temp sensor. I think the actual range is around 78ish to 106ish degrees.

Shawn

 

[shawn]

Yes, I changed it. Easy to change if one can solder, it was a through hole component. I'll grab a picture of the change.

Shawn

Just opened it up and I was mistaken. It is surface mount but I used through hole resistors. The red and black wires are from the temperature sensor. I added resistors from the red to a ground point on the circuit board. You could also do the same by putting a resistor across the red/black wire. I found the value by trial and error. Just added resistance until the heater turn on/off was within the adjustment range when the temp. sensor was in water around 104 degrees. The only reason there are multiple resistors is I didn't have the proper value by itself.

You could get fancy and put the resistors on a switch to allow the heater to go back to its normal range for B&W processing too.

Shawn

 

[brbo]

Rotary processing C41. The tempering bath isn't fixed at 104 degrees you can adjust it. The controller has a range from "67-93" degrees. The modification alters the signal from the temp sensor. I think the actual range is around 78ish to 106ish degrees.

Of course! I thought temp was fixed at 104F.

What C41 dev kit are you using? Some weird times and temperatures. Standard C41 is 3:15 at 100F. I've done side-by-side comparison with "alternative" temps and times. As nice as longer development times sound... the result is just not the same as standard processing.

 

[shawn]

Of course! I thought temp was fixed at 104F.

What C41 dev kit are you using? Some weird times and temperatures. Standard C41 is 3:15 at 100F. I've done side-by-side comparison with "alternative" temps and times. As nice as longer development times sound... the result is just not the same as standard processing.

I am using the Unicolor/Tetenal/Jobo press kit.

Shawn

 

[catamaran]

Heating Kit off the shelf

Heating Kit off the shelf

I have an off the shelf setup that has worked exceptionally well, takes little space (bathroom friendly) and almost too easy to use.
I use this device that maintains a perfect water temperature.
https://anovaculinary.com/anova-precision-cooker/
It hangs easy on the side of a large pot with a strainer. I'll place my C41 chem bottles in there to heat, and stay perfectly consistently heated, for however long I want to conduct a developing session.
For my pot I use the All-Clad 12-Quart Stainless Steel Multi-Cooker
[FONT=&quot]http://www.bedbathandbeyond.com/sto...quart-stainless-steel-multi-cooker/1012460112
The strainer insert allows the chem containers to sit in the water raised up off the bottom.
I just keep the dedicated pot and heater setup together and stored, and it takes about one minute to get it out, fill with water. Then maybe 10-15 minutes to heat chems to my target temp. A little alert goes off to let me know the temp has been reached. I can just cycle the containers in and out of the water, as I work a developing session, from a roll or two, to an all day developing marathon. The one thing I never have to think twice about is the water or chem temps being effortlessly accurate.
It made C41 developing so easy and effortless for me that I resumed use of color films on a large scale.
Hopefully they'll keep making color films. 🙂
Now, having provided that bit, about temp control, I have to add that currently I'm using room temp/stand developing for C41 more and more, as I'm loving the results of this method even more.
[/FONT]

 

[jamin-b]

I have an off the shelf setup that has worked exceptionally well, takes little space (bathroom friendly) and almost too easy to use.
I use this device that maintains a perfect water temperature.
https://anovaculinary.com/anova-precision-cooker/
It hangs easy on the side of a large pot with a strainer. I'll place my C41 chem bottles in there to heat, and stay perfectly consistently heated, for however long I want to conduct a developing session.
For my pot I use the All-Clad 12-Quart Stainless Steel Multi-Cooker
[FONT=&quot]http://www.bedbathandbeyond.com/sto...quart-stainless-steel-multi-cooker/1012460112
The strainer insert allows the chem containers to sit in the water raised up off the bottom.
I just keep the dedicated pot and heater setup together and stored, and it takes about one minute to get it out, fill with water. Then maybe 10-15 minutes to heat chems to my target temp. A little alert goes off to let me know the temp has been reached. I can just cycle the containers in and out of the water, as I work a developing session, from a roll or two, to an all day developing marathon. The one thing I never have to think twice about is the water or chem temps being effortlessly accurate.
It made C41 developing so easy and effortless for me that I resumed use of color films on a large scale.
Hopefully they'll keep making color films. 🙂
Now, having provided that bit, about temp control, I have to add that currently I'm using room temp/stand developing for C41 more and more, as I'm loving the results of this method even more.
[/FONT]

I am thinking of plunging into C41 and E6 home development using this method. One question from a novice - would I need to have metal developing tanks and reels for this to work properly or can I use the plastic ones (as I currently do for b/w developing)? In other words, is it essential to be able to maintain temperature while the chemicals are actuallly with the film, or is the temperature control only in preparation for filling the tank?