CO Barber cheat sheet

Hair has three layers: the cuticle (outer overlapping scales), the cortex (middle layer holding melanin and disulfide bonds), and the medulla (innermost core, sometimes absent in fine hair).

The growth cycle has three stages: anagen (active growth, about 2-6 years), catagen (transition, about 1-2 weeks), and telogen (resting, about 3 months, ending in shedding).

At any given time roughly 90 percent of scalp hair is in the anagen phase and about 10 percent is in telogen, which is why daily shedding of 50-100 hairs is normal.

Bond decision rule: water and heat break hydrogen bonds (temporary set), alkaline or acid solutions break salt bonds (pH change), and relaxers or permanent wave solutions break disulfide bonds (permanent change).

pH reference values: hair and skin 4.5-5.5; acid-balanced shampoo near skin pH; sodium hydroxide relaxer at about pH 12-14; ammonium thioglycolate waving lotion in the alkaline range.

Skin structure from outside in: epidermis (avascular protective barrier), dermis (contains follicles, sebaceous glands, sweat glands, and capillaries), and subcutaneous layer (fat and insulation).

Pigment rule: eumelanin produces brown and black hair; pheomelanin produces red and blonde hair; absence or reduction of both produces gray and white hair.

Vellus hair is short, fine, and non-pigmented and is generally unaffected by chemical services; terminal hair is longer, coarser, and pigmented and is the target of cutting, coloring, and waving.

Scalp anatomy landmarks used in barbering: frontal, parietal, temporal, and occipital regions; frontalis, occipitalis, and temporalis muscles; blood and nerve supply include the temporal and occipital areas.

Elevation rule: 0 degrees produces a blunt one-length line; 45 degrees produces graduation; 90 degrees produces uniform layers; 180 degrees produces long layers with the most movement.

Guideline types: a stationary guideline stays in one place and builds weight; a traveling guideline moves with each subsection and removes weight; a combination cut uses both.

Clipper guard sizes increase in 1/8-inch steps: #1 = 1/8 inch, #2 = 1/4 inch, #3 = 3/8 inch, #4 = 1/2 inch, and #8 = 1 inch.

Cross-check by cutting in the direction opposite the original section; if the two sides do not match, the cut is unbalanced regardless of how it looks from the front.

Porosity test: a strand that floats is low porosity, one that sinks slowly is normal, and one that sinks quickly is high porosity and needs lighter conditioning and gentler chemistry.

Elasticity test: wet a strand and stretch it; normal hair stretches about 50 percent and returns, while hair that snaps or stays stretched is too fragile for chemical services.

Conditioner works by lowering pH, smoothing the cuticle, and restoring moisture and protein balance after the alkaline action of shampoo.

Distribution and tension rule: distribute hair at a 90-degree angle to its base for even lengths, and maintain consistent tension so the finished line is not shorter on one side.

Texturizing or thinning shears have notched teeth and remove bulk mid-strand; they are used sparingly, away from the scalp, and never as a substitute for a properly elevated cut.

Shaving direction decision rule: with the grain for sensitive or easily irritated skin, across the grain for a medium result, and against the grain only when the closest possible shave is requested and tolerated.

Razor angle: hold the blade at roughly 30 degrees to the skin and keep the skin taut with the free hand using short, overlapping strokes.

Neckline rule: place the beard neckline just above the Adam's apple or along the natural curve where the jaw meets the neck; a line set too low looks unkempt as it grows out.

Cheek line rule: follow the natural growth pattern from the outer corner of the mouth toward the ear, rounding the corner rather than carving a sharp angle.

Hot towel protocol: use a towel warm to the touch, never scalding, and replace it if the client reports burning; heat is contraindicated on inflamed, broken, or recently chemically treated skin.

Straight razor care: strop the hollow-ground blade before each use with the spine leading and the blade flat, hone periodically, and never test sharpness on the skin.

Lather is applied with a brush in upward circular motions to lift the hair and keep it standing, and the shave proceeds from the easiest, least sensitive areas to the most sensitive.

Consultation sequence: greet, ask open-ended questions about goals and hair history, listen actively, note contraindications, restate the plan, and confirm before beginning.

Aftershave products contain astringents to close pores and remove residue plus moisturizers to soothe; alcohol-heavy products are avoided on dry or sensitive skin.

Three levels of control: sanitation reduces germs on surfaces, disinfection destroys most pathogens on nonliving objects, and sterilization destroys all microbial life including spores.

Disinfection rule: use an EPA-registered hospital-grade disinfectant, clean debris from the implement first, then immerse for the full contact time printed on the label (commonly 10 minutes).

Porous items such as nail files, wooden sticks, and cotton are single-use and discarded; nonporous metal shears, clippers, and combs are cleaned and disinfected between clients.

Sterilization methods are autoclave (steam under pressure), dry heat, and chemical sterilants, and are reserved for items that contact blood or broken skin.

Hand washing rule: wash with soap and warm water for at least 20 seconds before and after every client, and use an alcohol-based sanitizer only when hands are not visibly soiled.

Exposure rule for a cut or blood spill: stop the service, don gloves, clean the wound, disinfect the area and implements with an EPA-registered product, and dispose of contaminated materials in a closed container.

Refuse service and refer to a physician for contagious conditions including tinea (ringworm), pediculosis (lice), scabies, impetigo, and conjunctivitis.

OSHA Hazard Communication requires a Safety Data Sheet on file for every chemical product, covering hazards, safe handling, storage, and first aid.

Business formulas: gross profit = revenue minus cost of goods sold; net profit = revenue minus all operating expenses and taxes; retail markup is usually calculated on cost, not on selling price.