"Rodinal can be used for contrast control by varying the dilution, allowing you to use a single bottle to produce negatives to suit your requirements. The recommended 1+50 diluton produces crisp negatives of normal contrast with slightly more obvious grain than standard fine-grain developers. Lower dilutions (eg. 1+25) produce high contrast images; whereas at higher dilutions (eg. 1+75 or 1+100) Rodinal has a compensating effect and can be used to render high contrast scenes with normal contrast."

All right here:

http://www.digitaltruth.com/store/ca...nal-500ml.html