We have confirmed that short wave length ultraviolet irradiation, 2,500 Angstrom (A) to 2,600 A, from a low pressure mercury vapor source (cold-quartz lamp) elicits persistent tanning in the skin of normal Caucasians, despite contrary statements in standard dermatologic texts.
FREEDMAN RI, LEVAN NE. Pigmentation in Response to Cold Quartz Light. Arch Dermatol. 1966;94(3):263–264. doi:10.1001/archderm.1966.01600270013002