Not looking to replace C-41 with any of this, ideally what I want is two things from two different formulations:

1) A large speed losing contrast increasing developer (would like the same amount of stops of range on the neg in a straight line but a steeper line.. ie reaching a higher dMax on the straight line), to only develop the fine grains and perhaps provide a solvent effect .

2) The extreme other end. As useful as possible for underexposed images.

Quote Originally Posted by Photo Engineer View Post
Dan, very fine results and yes, I did know you were in AU. It was late at night here as you can see, and I wanted to kid you rather than post a long answer.

I think that you have the problems ironed out. Just watch for the contrast difference. ECN is about 0.5 and regular C41 films run from 0.6 (pro films) to 0.75 (consumer films), and thus the color print materials and scanners are fooled by thinking that all negative films are C41.

As for divided developer keeping, that remains to be seen. CDs oxidize more rapidly and are trickier to stabilize. You can make a B&W concentrate that lasts years, but CD kits are known to go bad rather quickly, even as a 3 part kit.

Ignore the 'ideal' results, and think of the C-41 measured results as the ideal results, and compare those with the split-bath measured results, that shows hue shifting from the C-41 results.

I will see what the gamma for the red, green and blue parts are to balance the grey scale vs the C-41 charts.. that should also be telling. If the gamma/contrast of one part (say green image) is significantly lower than the others for example, you may have prints with either green shadow cast or magenta highlight cast depending on printing.

Quote Originally Posted by chuck94022 View Post
Ok, this is all very cool. I don't understand it all, but it does seem that a divided C-41, while not perfect, is interesting.

Allow me to ask the related question of divided developers: does the formula here result in working solution longevity similar to Diafine? Because it is divided, does it last "forever"?
It does not last 'forever', last time I tried it a while ago, I found it stopped working after 6+ months, I don't know exactly when as I didn't use it very often (only a couple of rolls). I also mixed it up with tap water and no chelating agent.

The other issue is iodide and bromide build up (in both bathes) and weakening of bath A from some development occurring, and dissolved silver build up from my addition of thiocyanate.

Which may change developer characteristics with usage, my recommendation would be to replenish an arbitrary amount - it should theoretically self-balance to an equilibrium point.

The preferred Bath A I would like to use, is with CD-4 with enough alkali to neutralise the H2SO4, and then HAS to set the desired pH, maybe with a weak alkali buffer to get an extra amount of HAS for better keeping properties.

It is still quite economical, regardless of that, Flexicolor is also very economical, the cost is generally all in the bleach. One can be very economical in C-41 one-shot if they keep and replenish the bleach (and fixer too I suppose).