Actually, the film’s speed is clearly printed on the cassette: 21 DIN / 100 ASA.
All developers that have produced good results with APX 100 can be used with Silvermax with (almost) unchanged development times and equally good results.
Best regards,
Klaus
Very good, thank you, I will use the times for APX100 at 400 ISO from the Massive Development Chart. Unfortunately, there are no times listed for APX100 and Silvermax developer.