Probert's book is a good introduction to the art and science. There are companies which serve the hobbyist market, and who can probably be found by googling terms like "hobby anodizing". Please try to understand chemical safety, including the need for goggles, gloves, and ventilation; and a...
Some of these companies are listed by finishing.com. Just dip a cotton ball in black dye and swab it on, then rinse it off. If any dye remains visible to the naked eye, then it ain't sealed ! Robert H Probert Robert H Probert Technical Services Garner, North Carolina 2005 A. The ...