this may be a strange question, but when one talks about measuring how much a hairline has receded, and says that a normal (“Mature”) hairline recedes a half inch in the front, and an inch and a half at the corners, how do you measure that? vertically, as if straight down the face to a point parallel to where the hairline initially was??
The measurement of the mature hairline is essentially done with a drop string (gravity), from the leading edge of the hairline and to the highest wrinkle of the furrowed brow. Here’s a list of past posts that may help: