Chemist Walter McCrone identified the substance as a combination of red ochre and vermilion tempera paint; others have specifically identified it as type AB blood, with no evidence of any artificial pigments.

• 化学家沃尔特认定物质是由赭色和朱红色的蛋彩画颜料涂上去；其他人特别是把它鉴定为AB血型，没有任何人造色素的迹象。