The study or theory of “color” (Greek khrôma) found in Buddhist sources will be called here “Buddhist chromology.” Some readers may not like this term. But it does not matter. Those who do like my term may simply replace it with “Buddhist theory of color.” Here are some venues of exploration. First, the idea of color found in Abhidharma sources should be explored. Second, the idea of color in Vinaya sources may be explored. For example, what are the permissible colors? Also the practice of dyeing should be discussed. Third, how have colors been conceived of in later Mahāyāna sources? Fourth, the idea of colors in Buddhist Tantric sources should be investigated. In short, an attempt should be made to gain a diachronic and synchronic perspective of the Buddhist idea and use of colors and their significance.