Overview
Hair coloring is one of the most heavily tested topics on the NY Cosmetology State Board Exam, covering color theory, chemistry, safety protocols, application techniques, and color correction. A strong understanding of how color interacts with natural hair pigment — and how chemicals work inside the hair shaft — is essential for both the exam and professional practice. This guide consolidates all key concepts, definitions, and exam-critical relationships.
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Color Theory
The Color Wheel & Primary Colors
The color wheel is the foundation of all hair color decisions, from formulation to correction.
• Primary colors: Red, Yellow, Blue — cannot be created by mixing other colors; all other colors are derived from them
• Secondary colors: Created by mixing two primary colors
- Red + Yellow = Orange
- Red + Blue = Violet
- Yellow + Blue = Green
• Tertiary colors: Created by mixing a primary and adjacent secondary color
Complementary Colors (Critical for Correction)
Complementary colors sit directly opposite each other on the color wheel. They neutralize each other when combined.
| Unwanted Tone | Neutralizing Color |
|---|---|
| Red/Red-Orange | Green |
| Orange | Blue |
| Yellow | Violet (Purple) |
| Green | Red |
> 🎯 Exam Tip: The most commonly tested pairs are blue neutralizes orange and violet/purple neutralizes yellow.
Tone and Level
• Tone (Hue): Describes the warmth or coolness of a color
- Warm tones: Golden, copper, red-orange
- Cool tones: Ash, beige, smoky
• Level: The degree of lightness or darkness of a hair color, measured on a scale of 1–10
- Level 1 = Darkest black
- Level 10 = Lightest blonde
Contributing Pigment (Undertones)
Contributing pigment (also called underlying pigment or undertone) is the warm pigment exposed as hair is lightened. It follows a predictable sequence:
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Black/Dark Brown → Red-Brown → Red → Red-Orange → Orange → Yellow-Orange → Yellow → Pale Yellow
(Level 1–2) (Level 9–10)
```
> ⚠️ Watch Out For: Failing to account for contributing pigment is a leading cause of unexpected color results. Always factor in the undertone when formulating.
Key Terms – Color Theory
• Primary colors – Red, yellow, blue
• Secondary colors – Orange, violet, green
• Complementary colors – Opposite colors on the wheel that neutralize each other
• Tone/Hue – Warmth or coolness of a color
• Level – Lightness/darkness on a 1–10 scale
• Contributing pigment – Underlying warm tones revealed during lightening
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Hair Color Types & Chemistry
The Four Types of Hair Color
| Type | Developer | Lasting Power | Penetration | Lifts? |
|---|---|---|---|---|
| Temporary | None | Shampoo to shampoo | Cuticle surface only | No |
| Semi-Permanent | None | 4–6 shampoos | Slightly into cuticle | No |
| Demi-Permanent | Low-volume (5–10 vol) | 24–28 shampoos | Into cuticle/outer cortex | No |
| Permanent | Hydrogen peroxide | Until new growth | Deep into cortex | Yes |
> ⚠️ Watch Out For: Only permanent color mixed with developer can lighten natural hair. Temporary, semi, and demi-permanent colors deposit only.
Key Chemistry: Permanent Hair Color
Ammonia:
• An alkaline agent (raises pH)
• Swells and opens the cuticle, allowing color molecules to enter the cortex
• Without ammonia, color cannot penetrate deeply enough for permanent results
Hydrogen Peroxide (Developer):
• Oxidizes melanin — breaks down natural pigment to lighten hair
• Activates oxidative dye intermediates — small dye molecules enter the cortex and expand into larger, permanent color molecules
• Measured in volumes (percentage of peroxide concentration)
Developer Volumes – Know These Cold
| Volume | % Peroxide | Use | Lift |
|---|---|---|---|
| 10 vol | 3% | Deposit only, refresh color | 0–1 level |
| 20 vol | 6% | Standard permanent color | Up to 2 levels |
| 30 vol | 9% | More aggressive lift | Up to 3 levels |
| 40 vol | 12% | High-lift blondes | Up to 4 levels |
> ⚠️ Watch Out For: 40 volume causes significant hair damage and scalp irritation. It should never be used for routine retouch services.
Melanin – Natural Hair Pigment
• Eumelanin → Produces black and brown hair
• Pheomelanin → Produces red and yellow (blonde) tones
• Melanin is housed in the cortex of the hair shaft
Double-Process Service
A double-process service involves two separate steps:
1. Pre-lightening (bleaching) — removes natural pigment to the desired contributing pigment level
2. Toning/coloring — applies a toner or color to achieve the final target shade
> 🎯 Exam Tip: Double-process is required when the target color cannot be achieved in a single step — most commonly for very light blonde results.
Key Terms – Chemistry
• Ammonia – Alkaline agent that opens the cuticle
• Hydrogen peroxide – Developer; oxidizes melanin and activates color molecules
• Oxidation – Chemical process activated by developer
• Eumelanin – Pigment responsible for black/brown hair
• Pheomelanin – Pigment responsible for red/blonde hair
• Double-process – Pre-lighten then tone
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Safety & Patch Testing
Patch Test (Predisposition Test)
• What it is: Application of color formula to the skin (behind the ear or inner elbow)
• Why it's required: To test for allergic reactions to aniline derivative dyes found in oxidative hair colors
• When to perform: 24–48 hours before every color service
• Who requires it: Anyone receiving permanent or demi-permanent color (oxidative dyes)
• Positive reaction signs: Redness, swelling, itching, hives, burning
> ⚠️ Watch Out For: If a client shows ANY positive reaction, do NOT perform the service. This is both a safety and a legal issue. The exam will test this directly.
Strand Test
• What it is: Application of color to a small section of actual hair
• Purpose: Determines processing time, color result, and how hair responds to the formula
• When to use: Before or during the service — especially on resistant or damaged hair
• Not the same as a patch test — a strand test checks the hair; a patch test checks the skin
Which Colors Require a Patch Test?
✅ Permanent color — contains aniline derivative dyes → Requires patch test
✅ Demi-permanent color — contains aniline derivative dyes → Requires patch test
❌ Temporary color — no aniline derivatives → No patch test required
❌ Semi-permanent (non-oxidative) — no aniline derivatives → No patch test required
Key Terms – Safety
• Patch test / Predisposition test – Skin allergy test performed 24–48 hours before service
• Aniline derivative dyes – Chemical compounds in oxidative color requiring patch testing
• Strand test – Test on actual hair to preview results and processing time
• Positive reaction – Any allergic skin response; service must not be performed
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Application Techniques
Retouch Application
When applying permanent color for a retouch (regrowth) service:
• Apply color to the new growth only first
• Do NOT overlap onto previously colored hair
• Overlapping causes over-processing and creates a line of demarcation
Why the Scalp Processes Faster
Body heat from the scalp accelerates chemical processing, causing the hair nearest the scalp to lift and develop more quickly than the mid-shaft or ends. This is why:
• Color is often applied to the scalp area last in a first-time application on long hair
• Processing times must account for this heat factor
Fillers
A filler is used to:
• Restore missing warm/red pigment to over-lightened or porous hair
• Ensure even, predictable color results when going from light to dark
• Prevent uneven or muddy results after excessive lightening
> 🎯 Exam Tip: Fillers are applied before the target color when the hair lacks the necessary underlying pigment to support the final shade.
Highlighting Techniques
Foil Highlights (Traditional):
• Weaving technique — fine sections of hair are woven out and isolated in foils
• Lightener or color is applied; foil prevents product from touching adjacent hair
• Results in more uniform, consistent highlights
Balayage:
• Freehand painting technique — lightener is swept onto the surface of hair sections
• No foils used
• Creates a softer, more blended, sun-kissed effect
• More gradual, natural-looking result compared to foils
> ⚠️ Watch Out For: Balayage uses no foils — this is a key distinction the exam may test.
Key Terms – Application
• Retouch – Color applied to new growth only
• Line of demarcation – Harsh boundary caused by overlapping color
• Filler – Restores warm pigment before darkening over-lightened hair
• Foiling – Isolating sections with foil for controlled highlights
• Balayage – Freehand, no-foil painting technique
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Hair Color Correction
Line of Demarcation
• Definition: A visible, harsh boundary between two different colors on the hair shaft
• Cause: Overlapping permanent color onto previously processed hair during a retouch
• Prevention: Apply retouch color only to new growth
Color Removal
Color remover / Color reducer / Color stripper:
• Uses a reducing agent to shrink enlarged, oxidized color molecules
• Allows artificial pigment to be rinsed from the hair
• Does NOT lighten natural melanin — only removes artificial color
• Often used as the first step in color correction services
Understanding Unwanted Color Results
| Result | Likely Cause | Correction |
|---|---|---|
| Green | Ash color over gold/yellow undertone; blue + yellow = green | Apply red/warm toner; use complementary color |
| Orange | Insufficient lightening; residual red/orange undertone | Use blue-based toner or developer |
| Yellow/Brassy | Under-lightened pre-lightened hair | Apply violet/purple toner |
| Muddy/Uneven | Missing underlying pigment; porosity issues | Use filler before reapplying color |
Porosity and Its Effect on Color
Porosity = Hair's ability to absorb and retain moisture and chemicals
| Porosity Level | Characteristics | Color Behavior |
|---|---|---|
| Low porosity | Cuticle tightly closed; resists absorption | Slow to absorb color; may need longer processing; resistant hair |
| Normal porosity | Slightly raised cuticle; balanced absorption | Predictable, even color results |
| High porosity | Cuticle open/damaged; absorbs quickly | Grabs color fast; fades faster; may grab too dark |
> ⚠️ Watch Out For: High-porosity hair can grab color unevenly — often appearing darker at the ends. Apply color to ends last and reduce processing time.
Concerns When Lightening Previously Colored Hair
• Hair may be more porous and fragile than virgin hair
• Risk of over-processing, uneven lifting, and breakage is elevated
• Always perform a strand test and porosity assessment before applying lightener
• Previously colored hair may not lift evenly due to artificial pigment already in the cortex
Key Terms – Color Correction
• Line of demarcation – Visible boundary between two hair colors
• Color remover/reducer – Removes artificial pigment using a reducing agent
• Porosity – Hair's ability to absorb and retain chemicals
• Filler – Restores pigment before corrective darkening
• Toner – Applied after pre-lightening to neutralize unwanted tones
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Quick Review Checklist
Use this checklist in the days before your exam to confirm you've mastered every critical concept:
Color Theory
• [ ] Can name all three primary colors (red, yellow, blue)
• [ ] Know all secondary colors and how they are mixed
• [ ] Know all complementary color pairs and their neutralizing relationships
• [ ] Can identify the correct neutralizer for orange (blue) and yellow (violet)
• [ ] Understand the level system 1–10 (1 = darkest, 10 = lightest)
• [ ] Can describe contributing pigment and its sequence from dark to light
Chemistry & Color Types
• [ ] Know the four types of hair color and which ones require developer
• [ ] Understand that ONLY permanent color with developer can lighten hair
• [ ] Know what ammonia does (opens cuticle) and what developer does (oxidizes melanin, activates dye)
• [ ] Memorize developer volumes: 10 vol, 20 vol, 30 vol, 40 vol and their uses
• [ ] Understand the difference between eumelanin (black/brown) and pheomelanin (red/yellow)
• [ ] Know what a double-process service involves and when it's used
Safety & Testing
• [ ] Know patch test timing: 24–48 hours before every oxidative color service
• [ ] Know which colors require a patch test (permanent and demi-permanent)
• [ ] Know what a positive patch test reaction means: do NOT perform the service
• [ ] Understand the difference between a patch test (skin) and a strand test (hair)
Application
• [ ] Know to apply retouch color to new growth ONLY
• [ ] Understand why scalp hair processes faster (body heat)
• [ ] Know when and why to use a filler
• [ ] Distinguish between foil highlights and balayage technique
Color Correction
• [ ] Know what causes a line of demarcation and how to prevent it
• [ ] Understand how color removers work (reducing agent, does NOT touch natural melanin)
• [ ] Know how porosity affects color absorption and fading
• [ ] Know how to correct green, orange, and yellow unwanted tones using complementary colors
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> 💡 Final Exam Reminder: The NY State Board frequently tests patch test protocol, developer volumes, complementary color neutralization, and safety/contraindications. When in doubt, the safest answer is always to protect the client — if there's a positive patch test or signs of damage, do not proceed with the service.