What is the difference between C41 2-bath and 3-bath (other?) processes

Question

I am experienced B/W chemist but now I am entering into color processing at home. I am wondering what is the disadvantage of developing C41 film in 2-bath chemicals like Cinesitil Cs41 Color simplified kit and regular 3-bath, like Tetenal Colortec? Quality? Longevity of negatives? Or just a price? Also heard of other processes like Kodak 7-bath - any comment why so many steps?

Answer 1

The specific difference between the Cinestill 2-bath developer kit and the Tetenal 3-bath developer kit is that Cinestill leaves out the final stabilizer bath, or more precisely label it as 'optional'. They claim in their data sheet that modern C41 films contain embedded stabilizer chemicals, which are released during the first two baths, so that a separate final stabilizer bath is not necessary. Since the stabilizer bath is fast and easy to use, I am not sure if I personally would risk leaving it out.

Using or leaving out the stabilizer bath will not have any impact on the image quality, but may have impact on the archival properties of the resulting negatives. A typical stabilizer bath consists of an antifungal and a hardening agent. Since the emulsion is made of gelatine, it can be prone to fungal growth when stored, which is prevented by the first agent. The hardening agent makes the emulsion less prone to mechanical damage like e.g. scratching.

For home use, the number of baths in the original C-41 process has been reduced by combining multiple steps into one bath. I doubt that this has any, or significant impact on the image quality or archival properties of the negatives. It does however have impact on the durability of the chemicals. The working solution for most C-41 home use kits only keep a few weeks, while separate baths for large scale lab-development keep much longer and also have the ability to be replenished by replacing a small part of the working solution with fresh developer from time to time.

I have used Tetenal's 3-bath C-41 kit quite a lot and also made traditional wet-prints on paper from the negatives. I doubt that the results are in any way inferior to full-scale, 'many-baths' C-41 development. I would expect the Cinestill kit to be just as good.

Answer 2

The Kodak C-41 Color Negative Process, introduced in 1972 is an improvement over its predecessor, the Kodak C-22 Color Negative Process introduced in 1956. The C-41 process has evolved over the years becoming more environmentally friendly.

The steps:

1. Develop three minutes fifteen seconds
2. Bleach four minutes twenty seconds,
3. Wash in running water three minutes fifteen seconds
4. Fixer 1 four minutes fifteen seconds
5. Fixer 2 four minutes 15 seconds
6. Wash in running water three minutes fifteen seconds
7. Stabilizer one minute.

Total wet time about 23 minutes 35 seconds. Over the years, the process has been shortened.

Keep in mind, this film was designed to be processed to a color negative and then printed photographically on color photo paper. This chemical based paper requires precise exposure via an enlarger or automated photofinishing printer. The exposed paper was then developed in a similar wet chemical process. Because of the effort required to adjust the exposure the paper received, any irregularities in the film processing greatly complicated the adjustment of the paper’s exposure. The results of any irregularities are substandard prints and / or a high do-over percentage. In other words, maintaining the film process to specifications was vital.

Today, few color negatives are printed on chemical based photo paper. Those negatives selected to become prints on paper are likely printed using a computer driven device. These devices, and devices that display electronically color images, utilize software that has the ability to overcome most inaccuracies induced by an abbreviated developing process.

Bottom line, abbreviated film processes are commonplace. Perhaps these processes yield color films that have reduced archrival longevity. This can be mitigated by converting the film image to a digital image file.