I am not a lot of help with the process, but I once worked next to an electronic workshop that did small items all the time. I do know that they used a variable DC power supply, and an enamel tray full of electrolyte. I wish now that I had paid more attention to the process. What I do know is that they coloured the items by adding dye to the electrolyte so that it was deposited with the anodising. Sometimes it was food colouring and other times it was fabric dye. The coloured end products were bright and shiney, just like bought ones.