Quote Originally Posted by Michael R 1974 View Post
Hi Doremus, Mr. Bill, thanks for the feedback so far. I have a few additional thoughts:

1. When discussing ion exchange clearing baths as an aid to washing (HCA), Haist briefly mentions research pointing to the addition of clearing agents such as Sodium Sulfite, Sulfate and other compounds directly to the fixer, which could potentially eliminate the need for a separate HCA bath to improve washing/washing rates. At the time the book was written I guess there wasn't much on this yet, and it still concerned acidic fixers. Perhaps this is the "secret" behind purported faster washing with fixers like TF-4 or TF-5 rather than alkalinity per se (TF-5 is just slightly acidic). Perhaps people then incorrectly assume any alkaline fixer will wash out faster because TF-4 does.
Don't forget that C-41 process uses a near-neutral (~pH 6.5) fixer, and it was introduced long before Haist's book. So I'm pretty sure the Kodak folks were well familiar with non-acidic fixers.

Just about every common fixer (thiosulfate) contains a pretty fair amount of sulfite already, so I'm not sure how much would be needed to improve washing. I suspect it wouldn't be economical.

I don't know anything about the fast-washing fixers, so no idea why.

2. Haist mentions research and experiments that showed treatment of the print in an alkaline solution after fixation can help washing. However I find the section unclear. It seems to relate mostly to the emulsion and again deals with bringing the gelatin up to the isoelectric point. But it is not clear why it might help to raise the pH beyond the isoelectric point, nor are actual pH values discussed. Swelling is mentioned in reference to both the emulsion and the paper base, but it seems swelling can actually slow down the rate of washing the emulsion due to a longer diffusion path. It is not entirely clear to me what the conclusion is regarding the rate of washing the paper base. Swell seems to help, but swell vs what? Vs the state of the paper when it comes out of the acid fixer? Or vs a neutral state?
If Haist says research showed that, I'm sure it's legitimate. Too bad he didn't (or couldn't?) say more about it.

I think that iso-electric points vary with the exact gelatin, so maybe it's wrong to give a certain pH value. Just guessing. If the main issue is the amount of emulsion swell, the solution makeup is probably more important than pH. Lloyd West of Kodak published a paper, "Water Quality Criteria" in 1965. He showed graphs of emulsion swell in various solutions, and by far the greatest amount of swell was in distilled water, more so than in a color developer.

With modern materials, I'm not sure that they swell very much; I don't think so. There used to be special hi-temp fixers, etc, with a high salt content to limit swelling. But since modern color processes run at fairly high temp, you would guess that these are heavily pre-hardened. I'd guess that B&W emulsions are also, but again, this is guessing on my part.

3. Anchell makes the statement alkaline fixers wash faster than acidic ones. He doesn't really explain why other than to use laundry soap as an analogy, saying alkaline soap washed out of clothing fibers faster than an acidic detergent would. In Anchell/Troop the authors also cite faster washing as a benefit of alkaline fixers, although this is in relation to film, not paper (The Film Developing Cookbook).
Yep, that argument doesn't carry much weight with me. Back when I was a kid, I would have ate that up, but having spent a good part of my adult working life working with various process systems and the like, I've heard a large amount of B-S. So in the real world, I always ask people, "how do you know that?", then "Are you sure?" To really confirm what they know, the "beer test" is used, ie., would you bet beer on that? For some reason, even though they would be glad to buy you a beer, nobody wants to risk losing one in a bet.