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The universal level system runs from 1 (black) to 10 (lightest blonde), measuring lightness or darkness of the hair. Tone refers to the warmth or coolness within a level. Numbering above 10 is used in some lines but the core scale is 1-10.

20 volume peroxide provides approximately 1-2 levels of lift and full gray coverage, matching a 2-level lift from 6 to 8. 10 volume gives no lift (deposit only), 30 volume lifts 2-3 levels, and 40 volume lifts 3-4 levels and is generally reserved for high-lift formulations.

10 volume peroxide is a deposit-only developer used when the goal is to add tone or darken without lightening the natural pigment. Higher volumes progressively lift more underlying pigment as the percentage of hydrogen peroxide rises.

A single-process color combines lift and deposit in one application. A double-process requires first pre-lightening (bleaching) the hair to remove pigment and then applying a separate toner or color in a second step. Double-process is used for dramatic light blondes or fashion shades.

Cap highlighting places a perforated cap over clean hair, and a crochet hook pulls selected strands through the holes for lightener application. Foil highlighting wraps sections in foil for greater precision. Balayage is freehand surface painting; ombré is a graduated dark-to-light effect.

Highlights chemically lighten selected strands using a lightener or high-lift color (oxidation removes pigment). Lowlights use deposit-only or oxidative color to add strands darker than the existing base for depth and dimension. Either may be applied via foil, balayage, or cap.

Toners are typically demi-permanent or semipermanent products processed 5 to 15 minutes at room temperature, with the operator checking the color development every few minutes because over-processing leads to muddy or undesired tones. Manufacturer instructions always govern exact timing.

Common hair-typing systems describe type 1 as straight, type 2 as wavy, type 3 as curly, and type 4 as coily or kinky with a tight zig-zag, spring, or Z-pattern. Each type has subcategories (a/b/c) reflecting tightness. Texture (strand diameter) is separate from wave pattern.

Chemicals applied to broken or irritated skin can cause burns, systemic absorption, or severe reactions. Abrasions, scratches, open sores, or any signs of disease or irritation require the licensee to postpone or refuse the chemical service. Minor oiliness or normal dandruff alone is not a contraindication.

Resistant gray has tightly compacted cuticle scales. Pre-softening (mild peroxide application) gently raises the cuticle, and pre-pigmentation deposits a warm base so the final permanent color penetrates and looks balanced. Higher peroxide volumes alone risk damage and do not solve cuticle resistance.

Guanidine hydroxide is a no-lye relaxer formed by mixing calcium hydroxide with a guanidine carbonate activator. It is gentler on the scalp than sodium hydroxide (lye) relaxers but can leave hair drier. Sodium, lithium, and potassium hydroxide are lye relaxers.

Ammonium thioglycolate (thio) breaks disulfide bonds via reduction rather than the higher-pH hydroxide cleavage. Thio relaxers are milder and often used on previously color-treated or finer hair. Hydroxide relaxers (sodium, guanidine) are stronger and work by lanthionization.

Alkaline or cold permanent waves run pH 9.0 to 9.6 with ammonium thioglycolate, process at room temperature, and create a firm curl. Acid waves run pH 4.5 to 7.0 using glyceryl monothioglycolate, usually require heat, process more slowly, and produce a softer curl.

Slithering, also called effilating, glides the razor (or open shears) along a section to taper and remove bulk while softening ends. Point cutting jabs the tips of the shears into the ends for texture. Razor work is generally performed on wet hair to avoid splitting the cuticle.

Fine, fragile, or chemically processed hair should be styled under 300°F (about 150°C) to limit cuticle damage. Medium hair generally tolerates 300-380°F, and very coarse or resistant hair may need up to 400-450°F, but the lowest effective temperature is always preferred to preserve hair integrity.

A positive patch test (redness, swelling, itching, blistering) means the client is sensitive to ingredients in the formula, most often PPD. The service must not be performed; the client should be advised to consult a physician. Diluting or changing developer does not eliminate the allergen.

Board sanitation rules require single-use items (neck strips, applicator brushes, etc.) to be discarded and multi-use tools (combs, clips, shears) to be cleaned and then disinfected with an EPA-registered, hospital-grade disinfectant before reuse. Capes that touch skin must be laundered or covered with a clean neck strip.

Spiral perming produces a uniform, corkscrew curl from scalp to ends, which is the visual effect the client wants. It requires long, straight rods (or specially designed spiral rods) wrapped vertically along the strand so that each rotation produces a fresh turn of the helix. Concave rods wrapped horizontally produce a 'croquignole' curl pattern that is tightest at the ends and loosest at the scalp, not a spiral. Bender rods produce a soft, irregular bend. There is no acceptable tool-free perm. California licensees perform perms under CCR Title 16 §979.4.

Weaving uses the tail of the comb to lift a very thin alternating selection of hair onto the foil, leaving an equal or thicker section out. The result is a fine, dimensional, soft-blend highlight, ideal for a sun-touched look. Slicing (option A) takes a single solid slice, producing thicker, higher-contrast stripes. Cap highlighting (option C) pulls strands through a perforated cap and produces a uniform pattern but is not foil-based. Balayage (option D) is freehand painting that is generally done without foil, and is also a different selection logic. California licensees perform color under CCR Title 16 §979.4.

Hair color is specified as a level (1 to 10 from darkest to lightest) and a tone (the reflective hue at that level, such as N for natural, G for gold, A for ash, R for red, V for violet). The tone tells the colorist whether the formula will pull warm or cool and is used together with the color wheel to neutralize unwanted tones (for example, a violet-based toner neutralizes yellow). Viscosity, processing time, and ammonia content are formulation properties not encoded in the level-and-tone label. California licensees apply oxidative color under CCR Title 16 §979.4.

Effective scalp massage uses the PADS of the fingers, never the nails, to perform slow, rhythmic, circular movements. The pattern typically begins at the front hairline and works back, and also from the occipital toward the crown, mobilizing the scalp over the cranium and aiding venous and lymphatic return. Pressure should be firm enough to move the scalp on the bone but not so hard that it tears hair. Option B scratches the scalp and is a contraindication for chemical services. Option C pulls on hair, not on scalp. Option A is not massage at all. Scope of practice is set under CCR Title 16 §979.4.

Clean four-quadrant sectioning gives the stylist control of the hair, isolates the subsection actively being cut, and ensures that elevation and finger angles remain accurate so that the cut is consistent and reproducible. It also keeps unsectioned hair out of the line of the shears, reducing accidental cuts. Speed of blow-drying, shampoo volume, and visual elongation are unrelated to sectioning. Scope-of-practice for cutting is established under CCR Title 16 §979.4 and the BBC's enabling statute.

Going darker on previously lightened hair requires REPLACING the underlying warm pigment that bleaching removed; without it the deposit looks ashy, dull, and 'green' because the hair lacks its red-orange contributing pigment. The professional correction is to pre-pigment (fill) with a warm gold/orange filler matched to the natural underlying tone at level 5 to 6, then immediately follow with a deposit-only level 5 cool-brown formula at 10 volume. Option B skips the fill and produces a muddy green-gray result. Option D uses a lifting formula when no lift is needed and ruins integrity. Option A substitutes an unknown drugstore formula for color theory. California licensees perform oxidative color under CCR Title 16 §979.4 and must understand contributing pigment to deliver predictable color.

Manufacturers use the terms inconsistently, but in common professional usage a GLOSS is a demi-permanent depositing color mixed with low-volume developer (often 5 volume) that lasts 4 to 6 weeks and refreshes tone and adds shine. A GLAZE is typically an acidic, no-developer treatment that coats the cuticle, deposits a faint tone, and lasts 1 to 2 weeks until it shampoos off. Neither term is federally protected. Neither contains lift agents. California licensees perform both services under CCR Title 16 §979.4. Option A invents legal protection. Options B and D mislabel the chemistry entirely.

Foil highlighting uses a thin woven or sliced section, saturated with lightener, sealed in foil from scalp to ends, producing a brighter, more uniform, edge-to-edge lift. Balayage (French for 'to sweep') is freehand-painted on the surface of the section, usually without foil, with heavier saturation toward mid-lengths and ends and a soft, blurry start, producing a graduated, sun-kissed effect with very little scalp lift. Both can be done with bleach or with permanent color; both can be applied to all colors of hair. California licensees perform both services under CCR Title 16 §979.4. Options A, B, and D state characteristics that simply are not true of either technique.

Many keratin smoothing systems contain methylene glycol (formaldehyde dissolved in water) or other formaldehyde-releasing ingredients. When the product-saturated hair is flat-ironed at high temperature, the solution releases free formaldehyde into the breathing zone of the stylist and client, often exceeding the Cal/OSHA permissible exposure limit (0.75 ppm 8-hour TWA) and short-term exposure limit (2 ppm 15 min). Cal/OSHA's Hazard Communication Standard §5194 requires accurate SDS disclosure, employee training, and engineering controls (local exhaust ventilation). Options A, C, and D minimize or misstate the hazard. The exam tests recognition that formaldehyde is the regulated airborne contaminant, not water vapor or CO2.

A SINGLE-process color completes lift (if any) and deposit in a single application of one formula. A DOUBLE-process service uses two distinct chemical steps in sequence: a pre-lightener (typically powder bleach plus developer) lifts the natural pigment to the required underlying level, then a separate toner or oxidative color is applied to deposit the chosen cool, neutral, or warm tone. This is the standard route to pale-cool blonde from a darker natural starting point. California licensees perform both processes under CCR Title 16 §979.4. Option A confuses re-application with double process. Options C and D invent rules with no statutory basis.

For a short-term wedding install with planned removal, sew-in wefts on braided tracks are very removable: the stylist clips the cotton or nylon thread, the wefts release, the cornrow tracks unravel, and the natural hair returns to its prior state without solvent, heat, or pulled-out strands. Fusion (option A) leaves keratin residue and requires solvent for removal. Micro-link (option B) is removable but can damage the strand at the bead point if installed too tightly. Tape-ins are usually applied with adhesive only, NOT with a fusion iron (option D mixes two systems). California licensees apply extensions under their general hair-services scope at CCR Title 16 §979.4.

Thio relaxers (ammonium or sodium thioglycolate, pH around 9 to 10) break disulfide bonds reductively by donating hydrogen; the bonds can be rebuilt in a new position by an oxidizing neutralizer, the same as in a cold perm. Hydroxide relaxers (sodium, lithium, potassium, or guanidine hydroxide at pH 12 to 14) act by lanthionization: the disulfide bond loses a sulfur atom and becomes a single lanthionine bond that is permanent and irreversible, so an acid-balancing neutralizing shampoo (not peroxide) is used afterward to lower pH. Knowing the difference is critical: NEVER apply a thio over a hydroxide-relaxed head or vice versa, because the chemistries are incompatible and cause breakage. Cal/OSHA §5194 SDS hazard disclosure covers both classes.

Cosmetology scope in California covers cosmetic, non-invasive scalp and hair treatments: clarifying shampoos, OTC scalp masques, manual exfoliating scrubs, hot-towel and steam treatments, and relaxation massage. Diagnosing conditions like seborrheic dermatitis (option A), administering prescription drugs, performing PRP injections (option B), or piercing the skin with a dermaroller of any depth (option C) is the practice of medicine or nursing and is OUTSIDE the scope of any BBC license. Suspected medical scalp conditions require referral. The general service scope and sanitation duties are set under CCR Title 16 §979.4 and the BBC's enabling statute.

A razor is held at a shallow angle (closer to parallel) to the strand so that the blade glides through, removing weight gradually and producing soft, textured ends. The hair must be DAMP, not dry, because dry razor cutting splits the cuticle. A fresh disposable guard or blade is used for each client per California single-use rules; a permanent straight-razor blade on multiple clients is prohibited because porous/edge surfaces touching skin cannot be reliably disinfected (the BBC requires single-use cutting blades that contact skin). Razor cutting is generally NOT recommended for fine or over-processed hair because it accelerates splitting. Scope and sanitation duties are set under CCR Title 16 §979.4.

California prohibits the use of methyl methacrylate (MMA) liquid monomer in nail products. Licensees must use ethyl methacrylate (EMA) or other approved monomers. MMA is brittle, hard to remove, and has caused injuries; a waiver cannot override a statutory ban.

California sanitation rules prohibit double-dipping wax applicators. Once a stick touches the skin, it must be discarded; the next application requires a fresh, single-use stick. This prevents transferring bacteria back into the wax pot.

Isotretinoin thins the skin and dramatically weakens its barrier. Waxing can lift live skin, leaving raw wounds and scars. The standard contraindication window is at least 6 months after the last dose. A cooler temperature or patch test does not eliminate the risk.

Standard safe practice is to test wax temperature on the inside of the practitioner's own wrist, where the skin is thin and sensitive. Testing on the client risks burning them, and a paper towel does not reveal how the wax will feel on skin.

Combination skin has different conditions in different zones, typically oily forehead/nose/chin (T-zone) and drier cheeks. Treatment must be tailored zone by zone rather than treating the whole face as oily or dry.

The facial nerve (cranial nerve VII) controls the muscles of facial expression. The trigeminal nerve (CN V) is mainly sensory for the face and motor only to the chewing muscles. Estheticians should know this when performing facial massage.

The trigeminal nerve (cranial nerve V) provides sensory innervation to almost all of the face through its three branches: ophthalmic (V1), maxillary (V2), and mandibular (V3). The facial nerve is mostly motor.

A standard facial starts by cleansing the skin, then removes dead cells with exfoliation, optionally extracts where appropriate, moves into massage, applies a treatment mask, tones, moisturizes, and finishes with SPF for daytime sun protection.

Manicurists must NOT cut living tissue. The proper technique is to soften the cuticle, gently push it back, and only trim already-loose dead skin if necessary. Cutting living cuticle or the eponychium can cause infection and is outside safe practice.

A California manicurist license covers care of the nails and surrounding skin of the hands and feet. Facial skin services such as eyebrow waxing are outside scope; that work requires an esthetician or cosmetology license.

A thickened, yellow, crumbling toenail is a likely sign of onychomycosis (nail fungus), which is a medical condition. Services on the infected nail are contraindicated. The proper action is to skip that nail and refer to a physician or podiatrist.

Paronychia is a bacterial infection of the soft tissue around the nail, often causing redness, swelling, and pus. It is contraindicated for cosmetic nail services; the client should be referred to a physician for treatment.

Gel polish contains photoinitiators that begin polymerization when exposed to specific wavelengths of UV or LED light. Without proper light exposure for the required time, the gel will not fully cure, which can cause skin allergy and lifting.

California sanitation rules require foot spas to be drained, cleaned of all visible debris, and disinfected with an EPA-registered hospital-grade disinfectant between every client, leaving the disinfectant in contact for the time stated on the product label.

Reusable, non-porous metal tools must be cleaned of debris and then fully immersed in an EPA-registered hospital-grade disinfectant for the contact time stated on the label. Wiping or rinsing does not disinfect.

Porous or single-use implements absorb material and cannot be effectively disinfected. California requires that any such item used on a client be discarded immediately afterward. Reusing them risks transferring fungi and bacteria.

Estheticians are limited to superficial, non-medical exfoliating peels (typically light AHA/BHA products meant for licensed esthetic use). Peels that penetrate to the dermis are a medical procedure outside their scope, regardless of client consent.

Injectables are a medical act and must be performed by appropriately licensed medical professionals. Facials, makeup, and brow waxing fall within the esthetician scope.

Reactive, easily flushed skin that stings with new products is classified as sensitive. Sensitive skin needs gentle, fragrance-light products, lower-strength actives, and patch testing before introducing anything new.