The color of a freshly prepared aminophenol developer such as Rodinal is a pale lavender color when prepared from fresh reagent grade paraminophenol hydrochloride. It will remain this color for many years if stored in well sealed *glass* bottles. I know because I used to make it many years ago when I could not obtain Rodinal.
Unfortunately, Agfa replaced the original glass bottles with plastic which are not completely impermeable to oxygen. The result is that Rodinal now appears brown due to a small amount of oxidation. This does not effect its use. However, I would recommend transferring the contents of the original bottle to several smaller glass bottles especially if you are not intending to use the contents within a short period of time. The same advice applies to Kodak's HC-110.