Dandruff. Coloured scanning electron micrograph (SEM) of dead skin from the scalp (dandruff), a condition where there is an excessive shedding of dead skin cells. Dandruff can be the result of psoriasis, a fungal infection, or the overproduction of sebum, the secretion from sebaceous glands associated with hair follicles. Magnification: x35 when printed at 10 centimetres wide.