As a professional make up artist I rely on many tricks to create flawless finishes which last for hours and hours on the skin.
Of course I have access to a great many tools and products the average consumer doesn't usually buy or know how to use. However, most consumers want the same flawless finish with their make up as can be created by a professional.
The number one concern, in my experience, is that of durability. People want their make up to wear for hours and hours without having to fuss with it. To understand how to get make up to wear for prolonged periods of time it's important to understand how skin and make up interact with each other.
Make up adheres to the skin with surface tension. Surface tension is the elastic nature of liquids and gels which causes them to acquire the least amount of surface area possible. Total cohesion, of liquid molecules, is their natural physical state of matter which causes surface tension. The bulk of any liquid has each molecule equally distributed in every possible direction, by being "pushed" by an adjacent molecule, which results in a net force of zero.
In plain English this means liquid matter likes to evenly distribute itself over a surface area. The more even this distribution, the less energy the liquid requires to maintain its cohesion.
In make up emulsions oil is suspended in water and then assembles spontaneously into larger areas of mass. This allows for a very small amount of product to be distributed over the skin (a large surface area) and adhere with even and consistent coverage and colour.
If the surface tension is even then, theoretically, the make up can wear for hours and hours without touch up.
And here is where the problem occurs. Most people do not apply make up accurately. Foundation should really be applied with a foundation brush to ensure an even distribution of the product thus increasing the surface tension. If make up is not distributed correctly, the surface tension is compromised and so then is the durability of the make up.
The cosmetics industry's solution to this is the make up primer.
Primers are usually silicone based, intense moisturizers which seal the skin and create a very smooth surface (the more smooth the surface the more surface tension can be created). This in turn allows for uneven application of foundation (or any make up really) to spontaneously "push and pull" on itself thus creating perfect adhesion. With this adhesion durability is increased.
So the question begs: Do you really need a make up primer? The answer is maybe.
1. When applying foundation with your fingers - this is the least effective way of distributing make up and will almost always compromise surface tension.
2. When using a foundation which is made with heavy oil and waxes - for the record that is 95% of all foundations.
3. When the skin has uneven areas of hydration - if there are dry patchy areas of the skin a primer will ensure even distribution over the totality of skin.
1. When applying foundation with a proper foundation brush - this is different for every type of foundation and certainly takes practice.
2. When using an oil-free foundation - the downside is that it takes some time for these types of foundations to look natural on the skin (they need to blend with your natural oils to not look like "make up") so give yourself extra time when working with oil free formulas.
3. When working with powder make up - surface tension is only a consideration with liquids - powders will adhere just fine all by themselves.
Personally, I am a fan of fewer products with more results and as such I rarely, if ever, use a primer on my clients or myself. I simply work with oil-free and wax-free formulas and give them time to set on the skin (usually about 10-15 minutes). Once set, oil-free and wax-free formulas will wear as long as an oil based foundation which has been applied over a primer.
My favourite "primer not needed" foundations:
Designer/Spa Quality: Daniel Thompson Beauty Mineral Moisturizer wears for up to 15 hours with no primer needed. Variable coverage: Sheer, Medium or Full.
Department Store Quality: MAC Pro Longwear Foundation wears for up to 15 hours with no primer needed. Medium coverage.
Drugstore Quality: Revlon Colour Stay Foundation wears for up to 24 hours with no primer needed. Variable coverage: Medium or Full.
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