What Is It and What Does It Do?

“Not to prime is a crime!” says celebrity makeup artist Napoleon Perdis. Makeup artists everywhere sing the praises of primer, but do you need it? Is it worth the extra step? And what exactly is it? While most people are familiar with foundation and concealer, primer is a bit more mysterious. It was once considered unnecessary, but with the invention of high definition, primer has never been more important to disguise flaws and wrinkles. Even if you’re not in front of a camera, primer can help your makeup last all day.

Most makeup primers contain waxes, silicones, and polymers. According to WiseGeek, “[t]hese substances can form a bond with other cosmetics, causing the cosmetics to have more longevity than they would otherwise.” They give other makeup a smooth base to which they can adhere. Primers can stop lipstick from feathering and eye shadows from creasing. The smooth base can also fill in scars and noticeably large pores, plus cover redness, so you’ll have to use less foundation. According to Total Beauty, primers can even keep oil in check.

Primer is not one-size-fits-all; it comes in different shades and types to address different skin issues. Shades range from green to counteract redness, rosacea, and acne; mauve or light purple will fight yellow or sallow undertones in the skin; and pink brightens skin tone. There are also different primers for oily, dry, and combination skin tones so you can find the right one once you’ve diagnosed your skin type.

The key to applying primer is to wait until after you’ve applied your moisturizer and sunscreen. Primer acts as a kind of sealer for your skin; according to Jim Hammer, a cosmetics chemist who spoke to Total Beauty, applying primer is “like waterproofing your skin.” Water-based lotions and creams won’t be able to penetrate the silicone, wax, and polymer of the primer, so it won’t do any good to apply them after putting the primer on. Make sure to choose a light moisturizer, as heavier creams can cause the primer to slide off.

Once your skin has absorbed the moisturizer, the primer can create a “slick film on top of it,” according to Hammer. How your primer is packaged will dictate how you apply it. Some come in a spray bottle to be spritzed directly on your face. If it is in a pump or open-mouthed bottle, put a small amount into your hand and use a damp makeup sponge to dab the primer on your face. Makeup Talk suggests starting with the area under your eyes, then moving on to your nose, forehead, chin, and cheeks. Blend the primer into your skin, but feel free to have a heavier hand in areas like the T-zone where you need more coverage, or where makeup tends to wear away quickly. Let the primer dry for a few minutes before applying foundation and concealer.

Something to keep in mind about primers is that there are different kinds for face and eyelids. Normal primer shouldn’t be used on eyelids, but the special eyelid variety can help eye shadows stay put and prevent creasing. Makeup Talk says that eyelid primer can even make inexpensive makeup last.

While they add one more step to your makeup routine, primers may be worth it if they make all of your hard work last longer and provide better coverage. Even if you’re not willing to give up the extra time on a daily basis, consider using it for special events, like weddings, when you’ll need your makeup to be photo-ready for an entire day of cheek-kisses and dancing.