Getting back into photo and developing for the first time, I got a small variety of film, 100-400 speed range.

I wonder if there is a short list of film that do not work well with Caffenol, or Caffenol variables?

It depends on how low you set your expectations of what comes out. One variable is base fog, the other is excessive contrast. Don't want to consider grain, I expect it to be higher than in most commercial developers regardless of film brand.

I know that Rollei Retro 400 S is difficult to develop. But it's a long time I've had that film...

You are right. Rollei Retro 80S, 400S and Superpan 200 should be avoided with Caffenol, unless exposed seriously downrated (like -1.5 stops) and developed for a shorter time. Overdevelopment of these films eaily gives "unprintable" negatives. I am talking about common formulas like C-M, C-H, C-L. So, there you have your (conditional) list of bad performers. There are modified Caffenols adapted specifically to document films, they may perform better, but I have little experience with those. More films would be added if a separate problem of base fog is considered, if you absolutely cannot add some bromide. However, you can print through fog up to a point.

Pixophrenic said:

You are right. Rollei Retro 80S, 400S and Superpan 200 should be avoided with Caffenol, unless exposed seriously downrated (like -1.5 stops) and developed for a shorter time. Overdevelopment of these films eaily gives "unprintable" negatives. I am talking about common formulas like C-M, C-H, C-L. So, there you have your (conditional) list of bad performers. There are modified Caffenols adapted specifically to document films, they may perform better, but I have little experience with those. More films would be added if a separate problem of base fog is considered, if you absolutely cannot add some bromide. However, you can print through fog up to a point.

Click to expand...

Rollei Retro 80S works well in Caffenol CL. I've never tried Superpan 200. If you don't have Bromide, you can use iodized salt or table salt but a little more fogged and you need 10-12x more iodized salt and 20x for table salt.
Here you have a comparison between the three :

I am trying to understand the message that you convey with these examples. Are you unhappy that you have to use bromide? Obviously, with this film table salt is only marginally effective in fog suppression. But importantnly, contrast is low to normal. Since you can use bromide, I am wondering if you are able to read German, because the RPX400 technical sheet contains (as an official info by the film vendor Maco) conditions for development in Caffenol C-L for EI 800, Notably, it is suggested to add 1.2 g/L bromide and to develop at 24 C for 80 min with pre-soak and only initial agitation for 1 minute (stand). Excellent quality is promised. I hope this helps. And sorry to be patronizing, RPX 400 and Retro 400S are two very different films.

It was to show the difference between table salt, iodized salt and bromide, in case you can't find bromide...

fs999 said:

If you don't have Bromide, you can use iodized salt or table salt but a little more fogged and you need 10-12x more iodized salt and 20x for table salt.
Here you have a comparison between the three :

Click to expand...