Chemical Services – Illinois Cosmetology State Board Exam Study Guide
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Overview
Chemical services encompass permanent waving, chemical relaxing, hair coloring, and lightening — all of which alter the hair's internal structure through chemical reactions. Mastery of these topics is essential for the Illinois Cosmetology State Board Exam, as they represent a significant portion of both written and practical assessments. Understanding the chemistry, safety protocols, and contraindications for each service is critical to client safety and professional practice.
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Permanent Waving
How Permanent Waves Work
Permanent waving is a two-step chemical process that reshapes the hair's disulfide bonds using reduction and oxidation.
Step 1 – Reduction (Waving Solution):
Step 2 – Oxidation (Neutralizer):
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Types of Permanent Waves
| Type | pH Range | Active Ingredient | Notes |
|---|---|---|---|
| Alkaline (Cold Wave) | 9.0 – 9.6 | Ammonium thioglycolate (ATG) | Strongest; no heat needed |
| Acid Wave (True Acid) | 4.5 – 7.0 | Glyceryl monothioglycolate | Gentler; requires heat |
| Acid-Balanced Wave | 7.0 – 8.5 | Ammonium thioglycolate | Intermediate |
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Wrapping Techniques
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Key Terms – Permanent Waving
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Watch Out For ⚠️
> Over-processing: Leaving waving solution on too long breaks too many disulfide bonds, causing weak, frizzy, or disintegrated hair that cannot hold a curl. Always perform a strand test.
> Patch test vs. Strand test: A patch test (skin test) is NOT required before permanent waving because thioglycolate is not an aniline derivative sensitizer. However, a strand test IS always required.
> Under-processing: Too little processing time = weak, limp wave that drops quickly.
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Chemical Relaxers
How Relaxers Work
Chemical relaxers permanently straighten curly or wavy hair by breaking and rearranging the disulfide bonds. Unlike perms, the goal is straightness rather than a new curl pattern.
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Types of Relaxers
| Type | Active Ingredient | pH | Notes |
|---|---|---|---|
| Sodium hydroxide (lye) | Sodium hydroxide | 12 – 14 | Fastest; strongest; can burn scalp |
| No-lye (guanidine) | Guanidine hydroxide | ~13 | Two-component system; less scalp irritation |
| Thio relaxer | Ammonium thioglycolate | ~9–9.5 | Only reversible relaxer; can be re-permed |
No-lye relaxer components:
Sodium hydroxide process:
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Base vs. No-Base Relaxers
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Neutralizing After a Relaxer
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Critical Rule – Relaxer + Perm Incompatibility
> NEVER use a sodium hydroxide relaxer and a thio permanent wave on the same hair.
> Hydroxide relaxers permanently remove sulfur atoms through lanthionization — there are no intact disulfide bonds left for a thio wave to break, making the service both ineffective and potentially destructive.
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Key Terms – Chemical Relaxers
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Watch Out For ⚠️
> pH extremes: Sodium hydroxide relaxers have a pH of 12–14 — the highest of any salon chemical. Scalp protection is critical.
> Incompatibility: You cannot perm over a hydroxide relaxer. This is a frequently tested concept on the board exam.
> No-lye ≠ No chemical damage: No-lye relaxers can still cause scalp irritation and hair damage, especially with improper application.
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Hair Color Theory
The Three Categories of Hair Color
| Category | Penetration | Lasting Power | Contains Developer? |
|---|---|---|---|
| Temporary | Coats cuticle only | 1 shampoo | No |
| Semi-permanent | Slight penetration | 4–6 shampoos | No |
| Demi-permanent | Into cortex (partial) | Fades gradually | Low-volume developer |
| Permanent (oxidative) | Deep into cortex | Permanent | Yes |
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Developer Volume Guide
| Volume | % Hydrogen Peroxide | Lift | Use |
|---|---|---|---|
| 10-volume | 3% | Deposit only / tone | Darker shades, toning |
| 20-volume | 6% | ~1 level lift | Standard color application |
| 30-volume | 9% | ~2 levels lift | Lightening with color |
| 40-volume | 12% | ~3 levels lift | Maximum lift; fragile hair caution |
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The Level System
- Level 1 = Black (darkest)
- Level 10 = Lightest blonde (lightest)
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Color Theory & the Color Wheel
Primary colors: Red, Yellow, Blue
Secondary colors (mixing two primaries):
Complementary colors (opposite on color wheel) neutralize each other:
| Unwanted Tone | Complementary Neutralizer |
|---|---|
| Orange/brassy | Blue |
| Yellow | Violet |
| Red | Green |
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The Patch Test (Predisposition Test)
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Key Terms – Hair Color
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Watch Out For ⚠️
> Patch test is MANDATORY for aniline derivative tints — this is a legal requirement tested on the board exam. Skipping it is an exam failure point.
> Level ≠ Tone: The level system measures only depth/darkness. Tone (warm, cool, neutral) is a separate consideration.
> 20-volume is standard: Most permanent color uses 20-volume developer for one level of lift plus deposit.
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Hair Lightening & Bleaching
How Lightening Works
Lightening (bleaching) removes natural melanin pigment from the hair through oxidation. It does not deposit color — it only lifts.
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The 7 Stages of Decolorization
Hair passes through these stages in order during lightening (darkest → lightest):
1. Black
2. Brown
3. Red
4. Red-gold
5. Gold
6. Yellow
7. Pale yellow
> Toners are typically applied at Stage 7 (pale yellow) for maximum toner clarity.
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Toners
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Critical Safety Rule – Metallic Dyes
> NEVER apply on-scalp lightener to hair treated with metallic (progressive) dyes.
> Metal salts (lead, silver) in metallic dyes react violently with hydrogen peroxide, causing extreme heat, severe breakage, hair dissolution, and scalp burns.
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Key Terms – Lightening
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Watch Out For ⚠️
> Metallic dye incompatibility is a classic board exam scenario. If a client uses box color or progressive color at home, always do a strand test or metallic salt test before lightening.
> Toner timing matters: Applying toner too early (before pale yellow) will not achieve the desired result and may produce muddy tones.
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Chemical Safety & Contraindications
Pre-Service Assessments
Strand Test
Patch Test (Predisposition/Allergy Test)
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Hair Analysis Factors
| Factor | Definition | Chemical Service Impact |
|---|---|---|
| Porosity | Hair's ability to absorb moisture and chemicals | High porosity = absorbs fast → risk of over-processing; Low porosity = resistant |
| Elasticity | Hair's ability to stretch and return without breaking | Poor elasticity = weak/over-processed → contraindication for chemical services |
| Texture | Diameter of individual hair strand (fine, medium, coarse) | Fine hair processes faster; coarse hair is more resistant |
| Density | Number of hairs per square inch on scalp | Affects product quantity needed |
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Absolute Contraindications for Chemical Services
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Personal Protective Equipment (PPE)
Required in Illinois:
Strongly recommended:
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Emergency Procedures
Chemical in client's eyes:
1. Immediately flush with cool water for at least 15–20 minutes
2. Advise client to seek medical attention
3. Consult the product's SDS (Safety Data Sheet)
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Safety Data Sheets (SDS)
- Chemical ingredients
- Health hazards and risks
- Safe handling and storage procedures
- Emergency response instructions
- First aid measures
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Key Terms – Safety
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Watch Out For ⚠️
> Broken skin = absolute stop. Never perform ANY chemical service on a client with scalp abrasions, cuts, or skin conditions. This is both a safety and legal issue.
> Poor elasticity is a red flag: Hair that breaks when stretched wet cannot withstand chemical processing. This is a frequently tested contraindication.
> SDS is OSHA-mandated: Cosmetologists must know what an SDS is, where to find it, and what information it contains.
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