Electrolytic coloring of aluminum

Does anyone familiar of the electrolytic coloring aluminum?I’m running an experiment for my final year project…I couldn’t get any color…any pointers?

powder coating on aluminum i heard b4. but electrolytic no idea about it.

excuse the pun, but office staff here are wee bit ‘rusty’ on this!

simply… Anodising.
immersed into a bath, & current passed via anode/cathode
we suspect solution has an acid content, in addition to ‘colour dye’.

initial current is set up to remove outer ‘skin’ aluminium, the oxidation layer.
current then reversed & d alluminium anode plus soln. creates reqd affect…