Using a fix, then bleach before colour develop makes a colour negative using a b&w first developer step, instead of a positive. For good results of a positive, I've found the first dev needs to be hot ~39c like normal, otherwise even with a good b&w neg developed, the positives tend to have an extremely dense base/fog to them on top of the image.
For that particular image I think I just used E-6 colour developer, I've used CD-4 on others (C-41), results on E-6 film should be more or less the same, I've developed colour slides using Xtol as the first dev (40c), with C-41 as the colour developer, and the colours were fairly accurate then too.
Reversal works like this as you know:
b&w develop makes a silver b&w neg (on all colour layers) with no dye formation.
reversal exposure or fogging.
colour developer develops exposed undeveloped silver halide (positive) and oxidises simultaneously to form colour dye through the silver it develops as a mask.
bleach to convert metallic silver to silver halide.
fix to remove silver halide.
The other process I use works like this:
B&W first dev to make silver neg.
Fix to remove remaining silver halide, leaves onloy b&w neg.
Bleach to convert developed silver back to silver halides, which just leaves a negative image 'mask' of undeveloped silver halide.
Exposure of silver halide to light to make it easily developable.
Colour Developer to re-develop the negative image and form a colour negative.
Bleach to convert again silver back to silver halide
Fix to remove silver halide to leave no image apart from the colour dye.
You can skip the last 2 steps for a bleach-bypass effect.
Either way, this method allows to set tonality and contrast via first developer which the image forms through in a colour negative process, you could make a high contrast developer if you wish.. or have compensating effects (which the direct 2-bath C-41 should as well).
Rodinal 1+100 for 1 hour works very well with this. I found the "Diafine" (mixed up from a recipe posted on here) to be a tad thin for the first developer, maybe need to make it slightly stronger, or run it through twice etc.
Here is one when I first started.. is Rodinal 1+25 + ~5g of table salt (non-iodised) in 300ml solution on expired supermarket C-41 film, re-developed using the above process, with E-6 Colour Developer as the colour developer (which gives a green base, C-41 would probably keep it the normal colour base).
Last edited by Athiril; 04-09-2010 at 11:57 AM. Click to view previous post history.