The "Cultural History of Color" collection focuses specifically on artistic techniques. Click on "Browse Contents" to view all the collections available - they should all have a volume focused on antiquity.
(can also use DE5 .O9 1999)
Excellent resource for many aspects of the ancient world. The dictionary includes a good list of standard abbreviations for ancient authors and texts. It does not have every obscure mythological figure, but each entry has basic entry level bibliography on the topic.