Black and loose, The results were clear. As the report puts it: "The amount of heat gained by a Bedouin exposed to the hot desert is the same whether he wears a black or a white robe. The additional heat absorbed by the black robe was lost before it reached the skin."

 https://www.theguardian.com/science/2012/aug/19/most-improbable-scientific-research-abrahams