Hair Care and Haircutting
Structures you must know
Hair has three layers: the cuticle (protective outer scales), the cortex (the bulk, holding pigment and strength), and the medulla (a central core that may be absent in fine hair). The growth cycle runs anagen (active growth, roughly 2–7 years), catagen (transitional, about two weeks), and telogen (resting, about three months). Before cutting, assess texture, density, porosity, and elasticity; a wet strand that stretches and springs back has good elasticity.
The cutting mechanics
Three variables control every cut: elevation (also called projection - the angle the hair is held away from the head), distribution (the direction the hair is combed relative to the head), and the guideline (stationary, held at one fixed length, or traveling, which follows the previous section). Elevation drives layering: 0° gives a blunt, one-length line; 45° gives graduation with stacked weight; 90° gives uniform layers; 135° gives long layers and movement. Maintain even tension from section to section, cut wet for control, and cross-check to verify balance.
Traps
Questions often swap elevation for distribution, or imply that higher elevation always means a shorter perimeter (it removes weight, not necessarily length at the bottom). Another favorite: a traveling guideline follows the previous cut section while a stationary guideline does not move. Cutting past the guideline by even a few millimeters destroys the shape.
Worked example
A client wants lift at the crown but length preserved at the bottom. Hold the hair at 90° with a stationary guideline set at the crown: length shortens toward the top, creating volume while the perimeter stays long. Rule of thumb: elevation controls where length is removed; the guideline controls the shape.