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Permanent, demi-permanent hair, semi-permanent color - What's the difference?


What is Permanent Color & How Does it Work?

  • Permanent color typically comes as a color cream in a tube. It contains ammonia.
  • Tis color is then combined with a developer (or hydrogen peroxide) to form a color mix.
  • The resulting mixture is ultra alkali (high pH).
  • This mix opens up the hair cuticle, takes out the natural melanin in the hair cortex & replaces it with a new set of color molecules.
  • When you rinse the hair, the cuticles are closed once again and the hair is returned to its original position and chemical state.
  • The molecules that have been deposited into the hair cortex bind inside the hair hair cortex and as long as the hair cuticle is in good condition, essentially stay there forever.
  • Hence the name "permanent color". 

What is a Demi-Permanent Color & How Does it Work?

  • In a demi, the ammonia is replaced with a chemical called ethanolamine.
  • The ethanolamine in the color helps do the exact same thing as the ammonia in the hair color: create an alkali base so that coloration can take place.
  • In other words, mixed with the developer a demi also opens the cuticle, takes out the natural melanin and deposits hair color.
  • Typically a demi will lift hair less well than a permanent hair color.
  • Other than that it is essentially the same thing.
  • Both create an alkali base, both open up the cuticle, and both deposit color pigments into the hair cortex. 

Isn't a Demi Better for the Hair?

  • As we saw above, the two types of hair color work chemically in the exact same way.
  • Both belong for this reason to the class of hair color known as oxidative dyes.
  • The only difference is that with permanent hair color, ammonia is used, and with demis, ethanolamine is used instead.
  • Ammonia is the more effective of the 2 in terms of opening up the hair cuticle but it has a stronger, and fairly unpleasant smell: something similar to rotting eggs in fact! 
  • Ethanolamine opens up the cuticle less, but it smells more pleasant.
  • Consumers are sometimes persuaded to believe that because demis smell better and contain no ammonia, that as a result "they are not harmful" to the hair.
  • However, in reality, there is nothing particularly wrong with the ammonia - apart from the bad smell, of course!
  • Note incidentally, that not all permanent hair colors contain the same amount of ammonia.
  • The more lifting a permanent color is, typically the more ammonia it will contain.
  • So a high lift color would contain 2 or maybe 3 times as much ammonia as a level 3 hair color.

    Is there Any Different in the Color Result Between a Permanent and Demi-Permanent hair color? Which should I use when?

    • Demis typically lift less well than permanent hair color, and achieve less color vibrancy.
    • This is because ethanolamine typically opens the hair cuticle less than ammonia.
    • Demis care often used for grey hair coverage.
    • Demis are also used in tone down applications and in fact they are ideal for that.
    • But when you need to lift, or when you need an ultra vibrant color result, it would be better to go with a permanent color.

    Is Ugly Duckling Hair Color Permanent or Demi-Permanent?

    • Permanent. But we do add some ethanolamine into some of our permanent color in order to improve the cosmeticity and improve the smell. 

    Isn’t Demi-Permanent Supposed to be Better for the Hair than Permanent Hair Color?

    • It is true that demi-permanent dyes open up the cuticle a little less than permanent dyes.
    • However, the flip side is that demi-permanent colors tend to be less vibrant and may cover grey less well. 
    • Also, it is important to note that permanent dyes, when formulated the way that we formulate them at Ugly Duckling deliver Argan Oil and other essential conditioning agents right into the cortex during the coloring process. So, we color and condition at the same time.

    Are Toners Demi-Permanent or Permanent?

    • This is a brand-dependent question.
    • Redken's Shades EQ are demi-permanent hair colors.
    • Wella's T14 & T18 contain ammonia are therefore classed as permanent colors
    • Ugly Duckling's toners also contain ammonia are are also considered permanent colors.

    What Are the Advantages of Permanent Hair Color? 

    The advantages of permanent hair color from a stylist’s point of view are the following: 

    • Great range and choice of color.
    • Ability to go much lighter.
    • Ability to mix colors to produce creative and innovative effects.
    • Ease of Color Matching 
    • Perfect Grey Hair Coverage.Colors that last a long time

    What Are the Advantages of Demi-Permanent Hair Color?

    The advantages of demi-permanent hair color are:

    • Open the cuticle less, deposit color only.
    • Decent grey hair coverage.
    • Gradual Fade-out only after 6-8 weeks.

    What About Semi-Permanent Dyes? How do They Work?

    • Semi-permanent Dyes, otherwise known as Direct Dyes deposit pigments directly onto the surface of the hair.
    • You do not need to mix these dyes with developer.
    • They can produce vibrant color results.
    • Generally you would need to pre-lighten hair before using semis.
    • Ugly Duckling's Rainbow Colors are Semi-Permanent Hair Colors.

    What About Hair Bleach? How Does it Work?

    • Hair Bleach removes color from the hair through the process of oxidation.
    • This processes basically removes all the color pigments from the hair.
    • Which is why bleach can turn your hair completely white if left in long enough.

    Can Hair Color Provoke an Allergic Reaction?

    • According to studies, the vast majority (more than 98%) of women do not react to hair dyes.
    • For some rare women, however, the PPD (or paraphenylenediamine) or its close cousin PTD (or paratoluenediamines) present in hair dyes may provoke an allergic reaction on the scalp.
    • The exact cause of why some women have allergic reactions while most do not is still not known. However, it is observed that the development of these allergies typically happens after many colorings, sometimes after 10 or 20 years of successful coloring – it is as if the scalp suddenly “flips” from being non-sensitive to being sensitive.
    • Ugly Duckling's hair color contains Argan Oil, which does help to lessen the chemical impact of the PPD.
    • However, as we always tell our customers, our range is a range aimed at color vibrancy, blondes and fashion. And for that reason, you are going to get chemicals. They simply cant be avoided.
    • Ugly Duckling always recommends that you do a skin test first on your customer and wait 48 hours before doing a coloration.
    • And if you do have proven skin sensitivity and allergy issues, we would recommend you consult with your doctor first before using any hair color.

    Why Does My Scalp Itch When I Get It Colored and What Can I do About it?

    • The itching is primarily due to the developer, which contains hydrogen peroxide. This may cause the mix to feel itchy when applied. 
    • Ugly Duckling color contains added lanolin extract to place a protective layer over the scalp and provide for a more comfortable coloring experience - a silkier, more comfortable feeling on the scalp.
    • This additive ie being progressively added to most of our colors to provide greater comfort during the coloring process.

    About the author

    Sally has been a hair colorist and trainer for many years in both the US & Europe. She currently does hair color training for Ugly Duckling. She also helps develop new & awesome products for the brand.