CS41 development notes
02/29/2024
Bellevue, WA
A quick reference note on development times and methodology for Cinestill's CS41 two-bath kit for color C-41 home development. But mostly because I'm tired of looking all this information up every time it's been 3 to 4 months since I last developed some color film and need to look up all the temperatures and timings.
The CS41 comes in two varaieties, the powdered form or the liquid form. Both will make 1000ml or 1 quart of developer and develop about 24 color rolls. The main difference between the powdered form and the liquid form is that you have to mix them differently to create the 2 baths.
Start by mixing the chemicals to form the two baths.
Powedered instructions
| Color Developer Bath | Start with 600-700ml of water. Add and stir the contents of the Color developer package into a 1000ml container with the water. Top off to 1000ml with additional water. |
| Blix Bath | Start with 600-700ml of water. Add and stir the contents of the Blix package A into a 1000ml container with the water. Stir well. Then add the contents of Blix package B. This will create an endothemic reaction. Pour this solution back and forth between another clean pitcher. Then top off to 1000ml with additional water. |
Liquid instructions
| Color Developer Bath | Start with 20oz (591ml) the amount of water @ 120ºF (49ºC) to make 1quart (946ml) of developer. Add and stir the 8oz (237ml) of the Color developer bottle A container with the water. Then add 2oz (59ml) Color developer bottle B and C respectively. |
| Blix Bath | Start with 20oz (591ml) the amount of water @ 125ºF (51.7ºC) to make 1quart (946ml) of Blix. Add and stir the 8oz (237ml) of the Blix bottle A container with the water. Then add 2oz (59ml) Blix bottle B and C respectively. |
| Stabilizer/Final Rinse Bath (Optional) | Start with 30oz (887ml) the amount of water @ room temperature to make 1quart (946ml) of Stabilizer. Add and stir the 2oz (59ml) of the Stabilizer bottle with the water. |
Standard 6-step process for development
| Step name | Time | Tempurature | Agitation |
|---|---|---|---|
| Step 1: Optional pre-soak | 1 min | Developer temp | None |
| Step 2: Developer | 3:30 mins fresh | 105°F (39°C) | Continuous for first 10 sec., then 4 lifts or 4 inversion cycles every 30 sec. thereafter |
| Step 3: Blix | 8:00 mins | 75°F - 105°F (24°C - 39°C) | Continuous for first 10 sec., then 4 lifts or 4 inversion cycles every 30 sec. thereafter |
| Step 4: Wash | 3:00 mins | 75°F - 105°F (24°C - 39°C) | Running water or fill and empty tank 7 times |
| Step 5: Optional stabilize | 0:30 min - 1 min | Room | Agitate for the first 15 sec |
| Step 6: Hang dry | Overnight | < 140°F (60°C) | None |
Development time adjustments for multiple use of CS41
An 1000ml (Quart) size container of CS41 can develop up to 24 rolls of film.
The general rule is to add 4 seconds of development time per number of rolls already developed.
| # of rolls developed | Developer time |
|---|---|
| 0 (Fresh) | 3:30 min |
| 1 | 3:34 min |
| 2 | 3:38 min |
| 3 | 3:43 min |
| 4 | 3:47 min |
| 5 | 3:51 min |
| 6 | 3:55 min |
| 7 | 3:59 min |
| 8 | 4:04 min |
| 9 | 4:04 min |
| 10 | 4:08 min |
| 11 | 4:12 min |
| 12 | 4:16 min |
| 13 | 4:20 min |
| 14 | 4:24 min |
| 15 | 4:28 min |
| 16 | 4:32 min |
| 17 | 4:36 min |
| 18 | 4:40 min |
| 19 | 4:44 min |
| 20 | 4:48 min |
| 21 | 4:52 min |
| 22 | 4:56 min |
| 23 | 5:00 min |
| 24 (Max) | 5:04 min |
Note on pushing and pulling film
To push or pull film using CS41, adjust the time up or down. Note the numbers below are all for fresh chemistry with no rolls developed.
| Development | 102°F (39°C) | 95°F (35°C) | 90°F (32°C) | 85°F (29.5°C) |
|---|---|---|---|---|
| Pull -1 exposure | 2:45 min | 4:30 min | 6:30 min | 10:00 min |
| Normal exposure | 3:30 min | 5:45 min | 8:30 min | 13:00 min |
| Push +1 exposure | 4:33 min | 7:30 min | 11:00 min | 17:00 min |
Additional notes
- CS41 developer contains silver that can be bad for the environment. You can check with local photo labs to see if they can take your exhausted chemicals or check with your local city website for chemical disposal rules. Most cities or counties have days where you can drop chemicals off free. Do not pour in the sink or toilet.
- Some people online have gotten more than 24 rolls out of their CS41 kit, but most wouldn't recommend going past 24 rolls. Always check your chemicals for exhaustion with the stip test method before using ANY chemicals that have been used.
Opinions on CS41
After a long time in storage or many rolls or simply if I’m ever in doubt, I do a test strip of some film leader in daylight real quick, and make sure it comes out nice and dense. That’s good enough for me to know the dev and blix are working as they should. Any cloudiness or if it’s too light, time to toss em.
― Reddit user calinet6, 2022
Actually make an effort to maintain your temps and add approx. 4 sec per roll developed and you should be good for at least 15-20 rolls. Not following the instructions then being surprised when you get subpar results doesn't make a ton of sense to me.
― Reddit user drzombipdx, 2022
Resources
CS41 datasheet for powder most of the charts and data came from this page.
CS41 datasheet for liquid most of the charts and data came from this page.
CS41 product page on the Cinestill website.
Cinestill C-41 Development Times by Richard Sumilang.
Cinestill C-41 product page @ Freestyle photo & imaging supplies.