I'll add my procedures since they vary some from the previous posts:
Originally Posted by Wayne
- I use Kodak's Flexicolor chemistry exclusively and follow their instructions verbatim. The chemistry is getting harder to find but it's still possible to obtain here in the States from the minilab supply houses like Liberty, Unique Photo, etc.
- I process in a Jobo Autolab 2300. I've used Jobo CPA's and CPP's in the past. This level of automation in the 2300 allows very repeatable results which is critical in C-41.
- I monitor everything with Kodak process control strips and measure with my Macbeth densitometer. You really can't know if the process is running properly without control strips. Many will say they don't need this and have never had a problem. Point is, how do you know if you don't measure? As you can see with this point, I'm pretty serious about my C-41 results. You don't have to do it this way, but the process will wander on you if you don't measure and you can't tell by looking at the negatives until things are WAY off.
- I process sheet film primarily but also do some 120 and 135 roll film. Sheet film is 4x5 and 8x10. The 4x5 sheet film is processed in 3010 Expert drums and this works out OK. I used to use 3005 Expert drums for my 8x10's but have abandoned them in favor of a 3025 Expert drum lately due to uneven developing in the 3005. I know this may sound a little crazy since the Expert drums are supposed to be the best, but actually Jobo themselves warned against developing times less than 5 minutes in a rotary process. The C-41 development time is 3:15 and at 100 degrees F this development is very rapid. I've found that the chemistry has a hard time covering the entire sheet of 8x10 film in the first revolution or two of the 3005. The result is density variations across the 10" width of the 8x10 negative. And yes my processor is very level as is the drum. I'm very anal about that too. With the 3025 and two sheets of 8x10 I no longer have this issue. This problem only exists with the short development time of the C-41 process. B&W with its cooler process temps and longer development time causes no such issues and I use the 3005 Expert drum for my B&W work.
- I heat the chemistry to 38.4 C and use a 5 minute pre-heat but no pre-wash. Kodak and Jobo do not recommend a pre-wash. I use the slightly warmer 38.4 degree chemistry to compensate for the cool down that occurs when it first enters the drum. This was empirically derived using the process control strips. You can actually measure the density reduction of the slightly cooler developer if you don't compensate for this cool down effect.
- I use the developer one shot and follow Kodak's capacity specifications which are not as generous as some have listed in this thread. I can't speak for the Fuji kits but Kodak specifies 3 8x10 equivalents per liter of developer so that's what I use. I don't re-use since Kodak discourages that for rotary processes. Too much oxidation I believe. Bleach and fixer can be re-used once. Also, the Jobo drums list the volume required to cover the film, not the volume required to properly develop that film. So for the 3025 Expert drum and two 8x10's I use two-thirds of a liter. One of these days when I have extra time (laugh) I'll do some testing with process control strips to determine what the volume threshold is before performance degradation occurs. Until then I stick with what works. I'm not doing my own processing to save money.
- Download Kodak's tech sheets on C-41 from their website. There is a significant amount of technical info there and there are some notable differences in the Kodak specs from what has been posted in this thread. Not saying those other posts are wrong, just that the inventor of the C-41 process has published a great deal of technical info on the process and I do my best to follow it. In my younger days I ran a C-22 line in a large commercial lab and so was familiar with most of these procedures already. Adapting them to home darkroom use is fairly straightforward since Kodak and Jobo publish information on how to do it.
- Since you asked what others do, this is what I do. You don't have to do it this way. My procedures may be more complicated than some want to tackle. No worries. C-41 can be done very simply and without measuring and without tight temperature control. The results can be quite satisfying. They won't be as repeatable as they could be and the negatives may not always be developed as well as they could be but you can still print them. In the end, just get started and progress as far as you're willing to go. You'll be fine.
Be assured that your experiences are valued as much as anybody else's. Laostyle17 and I are going to do a dry run over Christmas with some c-41 that we really don't care about, but the second time through will be his wedding with my daughter. I never really expected to shoot my own daughter's wedding, but this better work, or he's going to have some real shitty wedding pictures.
I will be using either Jobo plastic on a Uniroller or stainless sitting in the constant-temp water bath.
You're down again, in case you didn't know.
I'm getting: Fatal error: Call to undefined function import_request_variables() in /home/polyglo2/public_html/wiki/lib/config.php on line 10
Originally Posted by polyglot
Originally Posted by langedp
How do you run the control strips in your JOBO? Do you run them in a separate pass in 35mm drum/reel, or do you add them to your sheet film drum, or something else? I'm thinking of adding control strips to my flow but not sure of a best way to do it.
A couple different ways depending on the drum I'm using and what control strip I happen to have. C-41 control strips come in several different formats. 35mm full frame and a smaller (narrower) format that I can't recall the name of. My current batch is the 35mm full frame strips. These can be put on a Jobo reel and run in a 1500 series tank. Assuming the process conditions are the same as your sheet film this works pretty well. I'll do this first to see where the process is and make sure the chemistry is still in good shape before running a bunch of film.
Originally Posted by anikin
The most reliable way is to run it in the same drum as the sheet film so that it sees the same process conditions as the sheet film. This way it sees the same agitation, temps, and developer exhaustion rates as the sheet film does. With the 3025 expert drum for 8x10's, I slide the strip in between two of the sheet film guides. I'll do this from time to time to make sure density and contrast conditions aren't drifting on me.
If you're using 3010 or 3005 expert drums it's a little harder but not much. I put little tabs of black plastic electricians tape on each end of the control strip. Insert this in one of the tubes on the expert drum and stick the ends down. The ends of the strip where the tape is don't get developed but the area where the control patches do. It works fine. If you're using 2800 series drums you can use this same method.
The 35mm full frame strips are a bit long for the 3010 4x5 drum so in this case just running it on a reel with the 1500 tank will get you going.
Woohoo! I developed my first C-41 sheets tonight. They came out...well, orange. So far so good. Back to do 4 more...