Reversal first development

[SalveSlog]

While my makeshift darkroom is warming up I philosophize a little. I'm prepared that you won't follow me and that this post won't get much response, but anyway:

There may be an analogy between the light from the enlarger that is hitting the paper and the b&w reversed film after bleaching and clearing.

We control the light from the enlarger and a perfect negative with
time and aperture
and
filters

After that, development of the paper is more or less to completion.

When trying to understand the reversal first exposure/development variables, would there be any gain comparing it to what we do with the enlarger?

 

[Gerald C Koch]

No, because most things in reversal work backwards.

To LIGHTEN a slide you must INCREASE the first development time. To DARKEN you DECRESE the time. People find this hard to get their minds around and it accounts for many problems.

The same reversed relationship also applies to camera exposure. If your slides are consistently too dark then you need to increase film exposure.

Development in the second (fogging) developer does go to completion however.

 

[SalveSlog]

Gerald,
that's kind of basic and I do understand that, but..

Is the hypo somewhat analog to the filters and the amount of light from the enlarger analog to developer strength etc. .. or something like that .. ?

 

[Gerald C Koch]

The purpose of the thiosulfate or thiocyanate in the first developer is to clear up the highlights. Without it the clear portions of the positive could be muddy. The amount of halide solvent must be carefully controlled as too much will also cause problems.

For a particular film the time in both developers is fixed regardless of camera exposure so there really is no analogy to making a print with an enlarger.

There is much less flexibility in reversal processing than in the conventional negative to positive process. This is why I encourage people to read and follow Ilford's method.

I'm not sure that I completely understand your posts. But I sense that you have sort of gotten off on the wrong foot in understanding reversal processing. Don't try to think in analogies. You need to fully understand each step in the process and what each implies. It is what it is.

 

[SalveSlog]

(Regarding my own posts I'm not shure I understand all of them myself!

I do use Ilfords method, but Ilford film is rather expensive in Norway. So I also try other films. And I prefer medium format. I think the Ilford recipe is written for 35mm/36exposures, though they don't state it. So it will take some experimets with developing times and hypo. Currently, inspired by Peter Carters results, I try Fomapan 100 which seems to need no hypo!