NIC Master Barber Theory key terms

To reduce the number of microorganisms on a surface or tool to a safe level, usually by washing with soap and water and wiping down. Sanitizing is a cleaning step; it does not kill every pathogen or destroy spores.

To destroy most harmful microorganisms, including many bacteria and viruses, on nonporous implements using an EPA-registered hospital-grade product mixed and used according to label directions. Disinfection is required for tools that contact skin or blood.

To destroy all microbial life, including spores, on an object. Sterilization is required by many state rules for implements that may have contacted blood, such as razors that nicked skin, and is done with an autoclave or approved chemical sterilant.

A product carrying an Environmental Protection Agency registration number on its label, meaning it has been shown effective against specific pathogens when used as directed. Barbers must follow label contact time, dilution, and shelf-life instructions.

The number of minutes a disinfectant must stay wet on an implement to kill the organisms listed on its label. Tools placed in or wiped with disinfectant and removed too soon are not properly disinfected.

The federal OSHA rule requiring employers to protect workers from blood and other potentially infectious materials. It mandates exposure control plans, hepatitis B vaccination offers, gloves, sharps handling, and training for anyone who may contact blood on the job.

An infection-control approach in which all blood and certain body fluids are treated as infectious regardless of the client's appearance or stated health status. Gloves and other barriers are used for every client when contact with blood or body fluids is possible.

A puncture-resistant, leak-proof, labeled container used to dispose of used blades, razor heads, and other sharp items that could carry blood. Sharps must never be tossed into ordinary trash or left on a work surface.

The Material Safety Data Sheet, now called the Safety Data Sheet, supplied by a product manufacturer. It lists hazards, safe handling, first aid, and disposal for chemicals such as disinfectants and relaxers, and must be kept accessible in the shop.

The practice of storing, labeling, mixing, and disposing of shop chemicals according to manufacturer directions and workplace safety rules. It includes keeping products in original containers, posting required notices, and training staff on hazards.

The three layers of a hair strand: the cuticle, a tough outer scale layer; the cortex, the main body holding pigment and strength; and the medulla, a soft core sometimes absent in fine hair. Each layer affects chemical and styling results.

The outermost layer of the hair, made of overlapping scales that protect the cortex. When scales lie flat the hair looks shiny and resists chemicals; when they are raised or damaged, hair is rough, porous, and absorbs products unevenly.

The middle and thickest layer of the hair, containing keratin bundles and melanin pigment. The cortex gives hair its strength, elasticity, and color, and it is the layer changed by coloring, lightening, and permanent waving.

The ability of hair to absorb and hold moisture or chemicals, determined largely by the condition of the cuticle. Low-porosity hair resists absorption; high-porosity hair absorbs quickly but may fade color fast and feel dry.

The ability of wet hair to stretch and return to its original length without breaking. Good elasticity signals strong, healthy hair; poor elasticity means hair is fragile and may not tolerate chemical services.

The natural pigment produced in the cortex that gives hair its color. Eumelanin provides brown and black tones, while pheomelanin provides red and yellow tones; the mix and amount determine a client's natural level and undertone.

The lightness or darkness of a client's untreated hair, rated on a scale from 1 (black) to 10 (lightest blonde). The natural level guides color selection and predicts how much lift or deposit a formula will produce.

The warm, neutral, or cool hue underlying a client's natural hair color, such as red, gold, or ash. Identifying undertone helps the barber choose a formula that neutralizes unwanted warmth or complements the skin.

A hydrogen peroxide solution, usually sold as 10, 20, 30, or 40 volume, that opens the cuticle and supplies oxygen to oxidize color or lightener. Higher volumes give more lift and more damage.

A dilute color formula applied after lightening to adjust or neutralize the resulting warmth and create the desired shade. Toners deposit rather than lift and are usually mixed with a low-volume developer.

A small skin test of a color, lightener, or relaxer product applied before the full service to check for an allergic reaction. Many states and manufacturers require it, typically 24 to 48 hours before the first application.

A test on a small section of the client's hair to predict how a chemical service will behave. It reveals processing time, color result, and the hair's tolerance before the barber commits the whole head.

A strong alkaline chemical product, usually containing sodium hydroxide or a no-lye alternative, that straightens curly or tightly coiled hair by breaking disulfide bonds. It requires careful scalp protection and strict timing.

A strong chemical link between sulfur atoms in neighboring keratin strands of the cortex. Permanent waves and relaxers break these bonds and then re-form them in a new shape during processing.

A product applied after a relaxer or permanent wave to stop chemical action and rebuild bonds in the new shape. Rinsing alone is not enough; the neutralizer stabilizes the hair and prevents continued processing damage.

Two relaxer types distinguished by how the scalp is protected. Base relaxers require a protective cream applied to the scalp before processing; no-base relaxers contain built-in protectants and are applied without a separate base.

A cutting technique in which the barber guides clippers along the spine of a comb to remove bulk while leaving a controlled length. It is used to blend sides and create tapered transitions without visible clipper marks.

A haircut in which hair length gradually shortens from the top or crown down to the neckline and around the ears, leaving no hard lines. Fades are described as low, mid, or high depending on where the shortest zone begins.

A plastic attachment fitted over clipper blades to control the length of hair left, labeled by number or millimeter size. Using the correct guard sequence is essential for even blending and predictable taper lengths.

To merge two areas of different hair length so no visible line or step remains. Blending is done with clipper-over-comb work, guard changes, and scissor-over-comb detailing to create smooth transitions.

The tilt of the razor against the skin and the amount of force applied during a shave. A shallow angle with light pressure removes hair close to the skin while reducing nicks, razor burn, and ingrown hairs.

A warm, moist soap or cream whipped to a rich foam and applied before shaving. Lather softens the beard, holds water against the hair, lubricates the skin, and helps the razor glide without irritation.

The direction in which facial hair grows. Shaving with the grain reduces irritation and ingrown hairs; shaving against the grain gives a closer result but raises the risk of razor burn, especially on sensitive skin.

Redness and irritation of the skin after shaving, caused by too much pressure, a dull blade, shaving against the grain, or insufficient lubrication. Prevention includes fresh blades, warm lather, and light strokes.

A razor stroke in which the barber's hand is not anchored on the client's skin, allowing movement over curved areas such as the jaw and neck. The barber must control the blade carefully to avoid cutting.

The process of examining the scalp and hair for dryness, oiliness, flakes, lesions, or signs of infestation before shampooing. Findings guide product choice and may require referring the client to a physician before service.

A contagious fungal infection of the scalp, sometimes called ringworm, marked by scaly patches and broken hairs. Barbers must not service affected clients and should refer them for medical treatment to avoid spreading infection.

Infestation of the hair and scalp by lice, which attach eggs called nits to hair shafts near the scalp. It is highly contagious, so the barber stops the service, disinfects tools, and refers the client for treatment.

A 0-to-14 scale measuring how acidic or alkaline a product is, with 7 neutral. Hair and skin prefer mildly acidic products; high-pH relaxers and soaps swell the cuticle, while low-pH rinses help smooth it.

A cut in which hair length decreases gradually along the sides, back, or neckline while the top stays longer. The taper is judged by smooth graduation and a clean outline at the edges.

The standards of honesty, confidentiality, and respect a barber follows with clients, coworkers, and the public. It includes keeping client information private, avoiding discrimination, and refusing services outside one's training.

The services and procedures a licensed barber is legally permitted to perform under state law. Working outside it, such as performing medical treatments, can lead to discipline, fines, or license loss.

The state-set conditions for holding and renewing a barber license, including required training hours, examinations, fees, and continuing education. Barbers must display the license and renew before expiration to keep working legally.

A routine check by a state board representative verifying that the shop meets sanitation, licensing, and record-keeping rules. Barbers should keep disinfectant logs, licenses, and SDS sheets available for review.

Permission a client gives after being told what a service involves, its risks, and its expected outcome. It protects both client and barber, especially for chemical services and services on minors.