Thermogram of a person's face just prior to taking an alcoholic drink. Thermography maps heat distribution over the body surface, giving a colour-coded image of temperature variation in one degree steps (see code strip at bottom). Blue is assigned to the coldest areas, and white to the warmest. A temperature reference disc (left of face) is calibrated at 30 degrees celsius. Compare with photograph M370/006, which shows an increase in temperature over the subject after having the drink.