As an alternate, assuming one requires such, try HC 110, if Kodak doesn't belly up too soon. Dilution B is best, for my ticket to the ball. Seek the dev times off the Massive Development Site. You will be pleased with the results, I think. I always have been.
I've tried the Rodinal and I'm happy with the results. I also tried stand development with it, and the negatives look good but I haven't had the time to scan or enlarge them yet. I think I'll stick with the Rodinal for a while and get to know it, and keep the others on the list of stuff to try. Why is that list always getting very long?
Rodinal and APX100 is a match made in heaven. Do mind that with a 1:50 dilution, you will only get about 50-64 in real speed. I would also suggest some tests because everyone else's opinion will only lead to waste and frustration. I just had my APX100 tested by Fred Newman at the View Camera Store, with a calibrated light source and 21 step tablet. Developed with Rodinal 1:50 @ 70 degrees, with distilled water throughout the process, and results were enlightening to say the least. Scary by how much I was off about everything.
Film speed is at most 64 with 16 minute development for an SBR of 5.8 (or less than N+1 if talking zone) and average gradient of 0.57. Normal development time for my tests, with SBR of 7 (N for zone) is 9.5 minutes @ 64ISO. Bottom line, if you rate the film @ 100ISO, which clearly it never reaches with Rodinal, and develop for some of the published times of between 12 and 17 minutes, you will be likely WAY off. Fred will do film testing for about $45. Best money ever spent.
Below is a PDF attachment if anyone is interested.
I think the AGFA method is every 30 seconds.
Max is correct, apx/retro needs at least 16 minutes. I usually developed it for 17 minutes @ 20°C but inverted the tank every minute.
btw:apx/retro is full speed in A49 or the in most Tetenal devs
A49 (old OrWo formulae, still made by Calbe) has some CD component in it which gives some speed loss. In 1+0 it gives more speed but then the sharpness is not very good. IMO you have always to dilute it.
An interesting combination is A49 with the Retro 80S. The film curve follows the regular curve pretty good. Rodinal and Retro 80S is a bad S-shape curve fitting. About the Retro 400S and A49 I still have to look at it. The film is OK but is slower then the indicated iso 400. BTW the same with the Retro 80S. Even in A49 1+1 hardly iso 50.