Red Seal Hairstylist key terms

A standardized document supplied with a professional product that lists its hazards, safe handling, first-aid measures, storage requirements and disposal instructions. Workers consult it before using unfamiliar chemicals.

A process that destroys most harmful microorganisms on tools and surfaces using an EPA-registered hospital-grade product, but does not reliably kill bacterial spores. Implements must be cleaned first, then fully immersed.

The complete destruction of all microbial life, including spores, usually achieved with an autoclave's pressurized steam. It is required for items that penetrate skin, such as some metal implements.

The presence of infectious material such as blood, pus or unclean water on a surface, tool or hand. Any item that becomes contaminated must be removed from service and cleaned before reuse.

A workplace rule that treats all blood, body fluids and non-intact skin as potentially infectious. It means wearing gloves and eye protection and using barriers regardless of whether a client appears healthy.

The design of tools, workstations and body positions to reduce strain and injury. For hairstylists it covers adjustable chairs, anti-fatigue mats, correct shears grip and alternating tasks to prevent repetitive strain.

A structured conversation at the start of a service in which the stylist asks about the client's goals, history, lifestyle and budget, then explains realistic options and confirms a plan before any tools are used.

A condition or circumstance that makes a proposed service unsafe or inadvisable, such as an active scalp infection or a recent metallic-salt colour application. The stylist must identify it and decline or modify the service.

Permission given by a client after the stylist has explained the service, its risks, expected results and alternatives in plain language. It should be documented, especially for chemical or corrective work.

A confidential form that records a client's contact details, service history, formulas, patch-test results, allergies and preferences so future services can be repeated safely and consistently.

A small amount of a chemical product applied to the skin, usually behind the ear or in the elbow crease, 24 to 48 hours before a service to check for an allergic reaction.

A test on a small cutting of the client's hair, using the actual product and timing planned, to predict colour result, processing speed and possible damage before the full service begins.

A 0 to 14 scale measuring acidity and alkalinity, where 7 is neutral. Hair and skin sit near pH 5, so high-alkaline products swell the cuticle and low-pH products help close it.

A hydrogen peroxide solution, available in volumes such as 10, 20, 30 and 40, that supplies oxygen to lift natural pigment and develop oxidative colour. Higher volumes lift more but cause more damage.

Permanent dye formed when small colour molecules and hydrogen peroxide enter the cortex and combine into larger pigment molecules that cannot wash out. It requires a developer and grows out rather than fading.

A strong alkaline cream, usually sodium hydroxide or a no-lye alternative, that breaks the hair's disulfide bonds to straighten curl. It must be timed carefully and followed by neutralizing shampoo to stop the reaction.

The period a chemical product is left on the hair to complete its reaction. It starts when application finishes, must be timed by clock, and overrunning it can cause burns, breakage or unwanted lightness.

A low-pH shampoo used after a relaxer to stop the chemical action and restore the hair's normal acidity. Several lathers are needed, because residual relaxer can otherwise keep breaking the hair.

The angle at which hair is held away from the head before cutting, measured from the scalp. Zero to 90 degrees builds weight, while lifting above 90 degrees removes it and creates layers.

The first section of hair cut, which sets the length and shape that all following sections are matched to. It may be stationary, travelling or cut inside the perimeter.

Re-cutting across the original section lines in the opposite direction to confirm the shape is even. It reveals uneven areas that are hidden when hair is combed into its natural fall.

Also called a one-length cut, it is created by cutting all hair at zero elevation so every strand ends on the same line. It gives a solid perimeter with maximum weight and density.

A cut in which hair lengths build up in stacked layers, produced by cutting at a low elevation with slight over-direction. Weight increases toward the perimeter, giving volume and a rounded shape.

Cutting or thinning techniques that remove bulk, soften a heavy perimeter or create movement without changing the overall outline. Tools and methods include point-cutting, notching, slicing and thinning shears.

A gradual shortening of hair length toward the neckline and around the ears, often done with clippers and blending shears so the hairline fades rather than ending abruptly.

A barbering technique where the clipper is guided by a comb held against the head, cutting hair to a consistent short length and blending between longer and shorter areas.

The ability of the hair cuticle to absorb and hold moisture. Low porosity resists water, while high porosity, often from damage, lets moisture escape quickly and needs protein and gentle handling.

How far a wet strand stretches before breaking and whether it returns to its length. Good elasticity means healthy protein bonds; poor elasticity signals over-processing and warns against further chemical work.

The number of strands per square centimetre on the scalp, described as thin, medium or thick. Density affects how much hair is sectioned, how long chemicals process and how a cut falls.

An oily substance produced by the sebaceous glands that coats the scalp and hair, keeping them supple and water-resistant. Excess sebum contributes to oily roots and can weigh down fine hair.

A visual and tactile check of the scalp for redness, flaking, lesions, oiliness or tenderness, done before a service. Findings decide whether a service can proceed or must be referred to a physician.

A molecule in shampoo with a water-loving head and an oil-loving tail that lifts sebum and dirt from hair so it can be rinsed away. Anionic types clean strongly; milder types suit dry or colour-treated hair.

A product applied after shampoo that smooths the cuticle, reduces static and improves combability. It works by depositing conditioning agents on the surface and should be kept mostly off the scalp.

Partial or complete loss of hair from any cause, including genetics, illness, medication or stress. Stylists do not diagnose it but should avoid tension styles and refer clients for medical advice.

Drying and shaping wet hair with a hand-held dryer and a brush, using tension and heat to smooth the cuticle or build volume. The direction of airflow sets the finished shape.

Shaping hair with heat tools such as curling irons, flat irons and hot rollers. Tool temperature must match hair texture and condition, and a heat protectant reduces damage.

Any strand, weft, wig or extension attached to the natural hair to add length, volume or colour. Attachment must avoid excess tension on the scalp and should be removable.

A strip of hair, natural or synthetic, sewn or bonded together at one end so it can be attached in rows. Wefts add length, volume or colour and can be reused if removed carefully.

A close-fitting mesh or stocking cap worn over the scalp to hold natural hair flat and give a secure base for a wig. It protects hair and keeps the wig from slipping.

A wide, bowl-shaped attachment for a hair dryer that spreads airflow over a large area and softens the force, so curly hair dries without being blown apart.