bleach and fix vs. blix

[alanrockwood]

Here is a question about processing using bleach and fix vs. processing that uses blix. My question is not which is better. The question is whether, in an automatic machine set up to use bleach and fix, could you just use blix for both of those steps and have the process work OK?

Here is why one might want to know. Hypothetically one might have a machine that is programmed for separate bleach and fix steps, but only one only has the blix chemicals on hand.

 

[clayne]

Shouldn't make a difference. You could also just counter it by altering dilution.

 

[2F/2F]

Blix is a compromise. Ideally, the C-41 process uses separate bleach and fixer baths. There are two main problems with using blix. First, you are using half as much of each chemical as you should be using, and each one is twice as diluted as it is with a process with separate steps. Second, when the two chemicals are mixed together, their effectiveness degrades more quickly than normal.

The first problem can be worked with a bit by using extended blix times, which you can do with your machine by using blix for both the second and the third bath. In fact, a two-bath blix procedure will probably help you out, much like a two-bath black and white fixer is preferable if possible. This will give each of the two combined chemicals enough time to fully do their things to the degrees that they should. Doing this does not solve the second problem, however; shelf life will be longer with separate chemicals.