I saw different people use different dilutions for same film. For example different people who use for example FP4 some use 1:25, others use 1:50, others use 1:100 dilution, etc...
My question is what different dilutions do, that is what is difference between 1:25, 1:50, 1:100, that is why people use different dilutions for same film?
Oh, by the way, Rodinal is one shot developer , right?
The different dilutions of Rodinal are used to control contrast. The 1+100 dilution is good to tame a high contrast scene and for a rainy overcast day you might prefer the 1+25 dilution to increase contrast. The 1+50 Dilution is about normal.