Interrupting E6 process after color developer step?

I would like to try and compare a few bleach and fix methods for E6 but don't want to waste a whole roll of film on my first experiments. The tests would be carried out over a week or more so the film can't just stay in a water bath all that time.

Is it possible to wash and dry slide film after the CD step, keep it in dark and dry storage until I continue with the bleach&fix steps? Or would it degrade over time, rendering my comparison useless? If so, how much time do I have? Are there any ways to stabilize it between CD and bleach step?

After the CD use a 1% solution of Acetic Acid and then a good wash. Dry and you can keep the film for weeks this way.

We did this regularly for almost every product in order to do Bleach, Blix and Fix tests.

PE

Thanks a lot, Ron, this will make my experiments much more efficient!

Does the film need to be kept out of light during the time between CD and bleach?

No, because the silver has been developed by the first developer, reversal has been done, and the dyes constructed in the color developer. The processing steps can all be done in room light including and following the reversal. Light reversal works fine for me so I process E-6 in room light after the first stop bath and a short wash. If you go through the second developer, stop, and wash then you can dry the film for later testing. At this point the film contains the negative (silver) image and the developed reversed (silver) image that contains the dye positive image. The halides have all been processed and the dyes have been constructed.

After re-wetting and bleaching you will be converting all the silver back to halide. The fixer will remove all silver leaving you with the positive dye image. As PE noted, you should use a stop following the color developer as well as after the first developer. These stop baths must be separate from each other, i.e. don't use a common stop for both steps. Stop baths used for color processing should contain a small amount of sulfite as well, usually included as 1-2% bisulfite.

mts, a mix of silver and silver halide is hardly archival, that's where my question came from. If you interrupt E6 right after the CD step, you have such a non archival mix of silver and silver halides in that strip, plus a list of other substances, remember that extra clearing wash you need if you use a ferricyanide bleach. While my pics are maybe not all that worthy of preservation anyway, I certainly don't want any side effects if I make a test to compare different home brew bleaches/fixers/BLIXes.

I will do the stop bath with 1% acetic acid, then wash thoroughly, then keep the test strip in a dev tank once it's fully dried and will use it in the course of a few weeks.

I'm curious, what is the reason you don't just develop each test strip of film completely? If I understand you correctly, you will have to cut the film into pieces to test the different bleach/fix methods anyway.

If you look at the instructions of E6 kits, they are not made for 20 fold reuse - think of aerial oxidation after 20 such runs: 6:30 at 38°C! So I would not only save a lot of time from running the whole roll through the first couple of steps in one run, there is also a good chance that the developer would show visible deterioration after many runs - even if only one little test strip is in the tank.

The Silver and Silver Halide mix is going to be removed by the bleach so the properties of the mix don't matter. And, in properly processed E6 it is almost all Silver anyhow.

PE

Let's assume such a film strip was to hang in some heavily used darkroom for ages: if some of the silver would be converted to sulfide, would bleach&fix still stand a chance?

No, Silver Sulfide is not generally removed by Bleaches, Blixes or Fixes. We used to test for that problem. I have kept such strips though, it a good environment for months.

There are a few draconian measures that would remove Ag2S, but not without some problems.

PE