Acuspecial FX-21 formula (Better than Rodinal!)

[Leica Lurker 17]

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8 minutes ago, BillT said:

John asked why I published the formula half strength. The reason is that in order to get to full strength, Crawley added additional ingredients to help solubility and stability of the formula, and this system I did not consider myself at liberty to disclose. All of this is clearly explained on page 75 of The Film Developing Cookbook, 2nd edition, 2020. To be clear, FX 21 can be seen as a further diluted evolution of FX 14/Acutol, which I have not published. And I must make very clear that Crawley never let any of his commercial formulas alone. They were always being involved. He would expect people to make adjustments to suit the constant evolution of films. 

Bill, can I ask you what you consider to be an optimal developer for FP4 Plus and HP5 Plus films? I'm not sure if Acuspecial is the right one for these but I could be wrong.

[BillT]

That's a philosophical question! You're asking where is the sweet spot. I asked Steve Anchell what he thought and he said he likes DD-X with those films I explain in FDC2 why DDX is such a remkarabkel developer, perhaps the ultimate evolution of D-76. I think that particularly makes sense for HP5. For Fp4, I would never say no to FX 1. I like the ultimate sharpness, and I don't mind the midtone compression. But that's just the mood I'm in today. 

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[Leica Lurker 17]

12 hours ago, BillT said:

That's a philosophical question! You're asking where is the sweet spot. I asked Steve Anchell what he thought and he said he likes DD-X with those films I explain in FDC2 why DDX is such a remkarabkel developer, perhaps the ultimate evolution of D-76. I think that particularly makes sense for HP5. For Fp4, I would never say no to FX 1. I like the ultimate sharpness, and I don't mind the midtone compression. But that's just the mood I'm in today. 

Thanks Bill

DDX has a very good reputation but quite expensive. Geoffrey Crawley also designed Aculux as a fine grain all rounder, but I don't know if the formula was ever made public. Any ideas to what it might be?

[BillT]

Crawley's formulas for Aculux changed greatly over the years, and would be evolving now if he were still alive. A typical formula for Aculux (FX 24)  is printed on p. 60 of FDC2. It is closely related to the first developer for the Kodak E-6 process. In its last iterations, the First Developer replaced HQ with HQMS and the thiocyanate with DTOD. A modern Aculux-like formula would probably follow suit. A problem with this kind of developer is that it needs to be optimized for a particular film. The most important thing is varying the amount of the solvent (either thiocyanate or DTOD) until it is just right for the film and time/temperature you are using. If there is too much solvent, there will be the risk of mushy grain and dichroic fog. When the solvent is just right, this type of developer has a very good compromise between fine grain and high sharpness. The Kodak color people thoiught this was the best tech they could achieve. The black and white people came up with Xtol, which is a much more flexible type of developer, in that can be used with virtually all films without reformulating. The reason Crawley changed Aculux so often was that the sweet spot for available films kept on changing. Someone who wanted to try it out today with a given film could use the FX 24 formula as a starting point, and then vary the thiocyanate (or DTOD if they could get it) until the amount seemed just right. 

[Leica Lurker 17]

I know what HQMS is, but not sure of DTOD. As for Aculux being similar to the 1st developer of E6, perhaps Adox Atomal 49 would be a good replacement for Aculux. That I believe employs a reducing agent used in colour negative film processing.

Anyway Bill, many thanks for the Acuspecial formula which is good to know. Perhaps something I will try sometime.