I have read the colors and what they were used for were not always uniform among those that used them as part of a "religion" or as part of their "craft", there seemed to be certain colord that were used to accomplish a particular ends to a situation or was wished by whoever was using "candle magic", I use the term "magic" loosely in this context. Any informative book on alternative religions might include some of it but the most complete information I have found deal with the general heading of 'paganism", or try looking under "magic", "witchcraft", "curses", "cures", etc.