Acros FX-2 semi stand time recommendations

I had a pretty successfull trial run stand developing Acros in Photographers Formulary's modified version of FX-2, TFX-2. I doubled the dilution. Aggitated for one minute and again at thirty minutes, then full stand for another hour. Hour and a half total.

I forgot about presoaking, and I did get what look like tiny airbells. I also worry about uneven development with stand developing in general. Now I'd like to try semi stand development, aggitating perhaps every tenth minute.

I do not have a 'normal' development time for this combo to begin from, so could anyone reccommend a good place to start for ten minute aggitation intervals backed off from my 1 1/2 hour stand time?

Normal times for many films in TFX-2 are pretty long, in the 15-20+ minute range.

Thanks!

It's very possible that 1+1+16 is simply watering down TFX2 to the point that:
•there is too little metol to develop the film, and
•• the pH has dropped to make the glycin inactive
FX2 is basically a classic metol acutance developer, and the glycin is added to work in the midtones and highlights. (TFX2 is Troop's accomodation of Crawley's formula, for t-grain films, and is VERY similar to FX2) VERY VERY VERY similar.

It's very safe to use development intervals of 5 minutes with 120 film, and 10 minutes with 35mm. There is little to gain by extending the intervals beyond these times. If I were testing a new film, I'd double the published D76 time as a starting point. And I would not worry about airbells with this stuff. Pre Soaking may be fashionable today, but I'd beg you to skip it.

Finally, because minimal agitation raises the shadow density relative to the highlights, pivoting the curve on the midtones, base your EI a on V or VI, and not I. A very quick way to dial in a new film is to expose a roll at Zone V, and develop a strip, and run the process. If you have a liter tank, run 4 strips and pull the first reel at 10', one at 15, one at 20, and the last at 25. Contact print them.

Hi there DF,

You mention TFX-2 being very similar to FX2. Do you use the same development times for both, and at what dilutions?

I think FX-2 and TFX-2 have the same times. I like 1+1+8.
The instruction sheet from the Formulary is a superb place to begin.

Half strength FX-2 works OK, it is what Crawley originally suggested, its pH is about 11.Here's one on 35mm Adox 25 semi stand 50 min 68F agitate 30s at half-way in half strength FX-2. On the print there is a clearly visible edge effect in the sky on the RHS of the tower.There will be less edge effect with modern emulsion Acros but I would guess the time for agitation at 10 min intervals in half strength FX-2 to be of the order of 60 min.
IMO some uneveness at the edge of the negative is a good trade off for Crawley's 'interesting internal contrasts'.

My concerns about higher dilutions are related to the insistence of a pre-soaking step.