Developer volumes and how much they lift

Four numbers carry a disproportionate share of the coloring domain, and they are worth knowing cold rather than reasoning out under time pressure. Everything else on this page follows from what the volume number actually measures.

Questions and answers, explained

All 12 questions above, with the correct answer and why it is correct. Everything here is on developer volumes and how much they lift.

1. Which developer volume deposits color without lifting the natural level?

   • A10 volumeCorrect
   • B20 volume
   • C30 volume
   • D40 volume

   Why: 10 volume is the deposit-only strength, used with demi-permanent color and for toning. 20 volume lifts one to two levels and is the standard for permanent color and gray coverage; 30 lifts two to three and 40 lifts three to four. Choosing a higher volume for a deposit-only service adds lift and damage that the formula was never meant to deliver.

   Reference Clinical domain: hair coloring and lightening; developer strengths

2. A formula calls for two levels of lift. Which developer is appropriate?

   • A5 volume
   • B10 volume
   • C40 volume
   • D20 volumeCorrect

   Why: 20 volume is the one to two level lift and covers the great majority of permanent color services. 5 and 10 volume deposit without meaningful lift, so the target level would never be reached. 40 volume lifts three to four levels and would overshoot the target while adding avoidable damage.

   Reference Clinical domain: hair coloring and lightening; developer strengths

3. What is the oxidizing agent in a standard hair color developer?

   • AAmmonium thioglycolate
   • BSodium hydroxide
   • CHydrogen peroxideCorrect
   • DAmmonia

   Why: Hydrogen peroxide is the oxidizer; its concentration is what the volume number reports. Ammonia is present in many permanent formulas but it is the alkalizing agent that swells the cuticle, not the oxidizer. Ammonium thioglycolate is a reducing agent used in permanent waving, and sodium hydroxide is a relaxer base — neither belongs in a color developer.

   Reference Clinical domain: hair coloring and lightening; developer chemistry

4. What is the function of ammonia in a permanent hair color formula?

   • AIt raises the pH and swells the cuticle so color can enter the cortexCorrect
   • BIt oxidizes the dye precursors into finished color molecules
   • CIt seals the cuticle at the end of processing
   • DIt neutralizes unwanted warmth in the finished result

   Why: Ammonia is the alkalizing agent. Raising pH lifts the cuticle scales so the small dye precursors and the peroxide can reach the cortex. Oxidation is the peroxide's job. Sealing the cuticle is what an acid-balanced rinse or conditioner does afterwards, and canceling warmth is a function of the tone chosen, not of the alkalizer.

   Reference Clinical domain: hair coloring and lightening; developer chemistry

5. What results from overlapping lightener onto previously lightened hair during a retouch?

   • AA deeper, richer tone through the mid-lengths
   • BBreakage and a visible line of demarcationCorrect
   • CImproved shine because the cuticle is resealed
   • DFaster processing with no other effect

   Why: Overlapping subjects already-processed hair to a second chemical treatment. The result is weakened, over-lightened hair at the overlap and a visible band where it meets untreated hair. It does not deepen tone, it does not reseal anything, and the faster processing it causes is precisely the damage, not a neutral side effect.

   Reference Clinical domain: hair coloring and lightening; overlapping

6. Which lightener form must not be used directly on the scalp?

   • ACream lightener
   • BOil lightener
   • CPowder lightenerCorrect
   • DDemi-permanent color

   Why: Powder lightener is an off-scalp product: it is the strongest form, dries out as it works, and is intended for foils and other techniques that keep it away from skin. Cream and oil lighteners are formulated with conditioning agents that make on-scalp use acceptable. Demi-permanent color is not a lightener at all.

   Reference Clinical domain: hair coloring and lightening; lightener types

7. Which highlighting technique involves painting lightener onto the surface of the hair freehand?

   • ACap technique
   • BFoil technique
   • CBalayageCorrect
   • DDouble process

   Why: Balayage, from the French for sweeping, is freehand surface painting. The cap technique pulls strands through a perforated cap with a hook, and foiling isolates woven or sliced sections in foil. A double process is not a placement technique at all — it describes lightening and then toning as two separate steps.

   Reference Clinical domain: hair coloring and lightening; highlighting techniques

8. Why must lightener and developer be mixed in a non-metallic bowl?

   • AMetal reacts with the mixture and alters the resultCorrect
   • BMetal bowls cannot be disinfected
   • CMetal makes the mixture too cold to process
   • DMetal bowls are prohibited by Florida rule

   Why: Metal can react with peroxide and the alkaline components, changing how the product processes and the color it delivers. Metal implements are in fact non-porous and disinfect very well, so that is not the reason. Temperature is not the issue, and this is a chemistry precaution from the manufacturer rather than a specific Florida prohibition.

   Reference Clinical domain: hair coloring and lightening; mixing precautions

9. Equal parts of 20 volume and 40 volume developer are combined. What is the resulting strength?

   • A60 volume
   • B20 volume
   • C30 volumeCorrect
   • D40 volume

   Why: Mixing equal parts averages the concentration, so 20 and 40 give 30 volume. Volumes add only if you are adding more of the same strength, not when you are diluting one with another. The result can never be higher than the stronger component or lower than the weaker one.

   Reference Clinical domain: hair coloring and lightening; developer dilution

10. A lightener has dried out on the hair before reaching the target stage. What is happening?

    • AIt is processing faster than normal
    • BIt has stopped working and lift has haltedCorrect
    • CIt is depositing tone instead of lifting
    • DIt is sealing the cuticle as it dries

    Why: Lightener works only while it is moist; once it dries the oxidation reaction stops and no further lift occurs no matter how long it is left on. That is why powder lightener is often overlaid with foil or plastic and why drying out is a technique failure rather than a sign of progress. It does not begin depositing tone or sealing anything.

    Reference Clinical domain: hair coloring and lightening; lightener behavior

11. A gentle mixture of shampoo, lightener and developer used to lift a small amount of unwanted color is known as what?

    • AA soap capCorrect
    • BA double process
    • CA pre-softening treatment
    • DA chelating treatment

    Why: A soap cap or bleach bath dilutes the lightener with shampoo so it lifts gently and evenly, which suits a small correction or a build-up of deposited color. A double process is a full lighten-then-tone service. Pre-softening opens resistant gray, and a chelating treatment removes mineral deposits rather than dye.

    Reference Clinical domain: hair coloring and lightening; corrective color

12. Why must lightener never be applied to a scalp with abrasions or open sores?

    • AThe lightener would process unevenly around them
    • BThe color result would be too warm
    • CThe product would dry out too quickly
    • DBroken skin allows chemical entry and serious injuryCorrect

    Why: Intact skin is a barrier; broken skin is not. A strongly alkaline oxidizer on an open lesion causes chemical burning and can carry product into the tissue, so the service is postponed until the scalp has healed. Uneven processing, warmth and drying are all real technical concerns in other contexts, but none of them is why this is an absolute contraindication.

    Reference Clinical domain: hair coloring and lightening; contraindications

Drill the whole domain

• Hair Coloring and Lightening (19.5%)

Other topics

• Florida cosmetology license requirements
• Florida salon licenses and inspections
• What a Florida cosmetology license covers
• Salon disinfection rules, step by step
• Corrective color and the law of color
• Patch tests and strand tests
• Perm rods, wrapping and processing
• Hydroxide relaxers versus thio relaxers
• Nail disorders: when to refuse the service
• Gray coverage and resistant hair
• Waxing contraindications and safety
• Elevation and guidelines in haircutting
• Blood exposure in the salon
• Hair and scalp analysis before a service
• Thermal styling and heat safety

See all topics · Study Guides · Full practice exam