A primer is a lotion or gel that is applied to the face underneath foundation. Its job is to keep makeup from fading during the day - and it does this by preventing the makeup from "soaking" into the skin. It forms a barrier between your skin and your foundation.

Primers also smooth out the skin by filling in fine lines and pores. After applying primer and letting it dry completely, foundation will go on smoother, and the final look will be more "airbrushed."

And there are other benefits. Many women say that primers keep their makeup fresh and the color true, even in hot weather.

Some primers contain sunscreen, some contain oil-control ingredients, and some are hydrating. Laura Mercier has one for normal skin, one for oily skin, and one for dry skin. Paula Dorf 's primers come in normal/dry and normal/oily.

With a hydrating primer, especially one with sunscreen, you can skip your morning moisturizer altogether.

Here is the application order:
1.moisturizer (with sunscreen, unless the primer has sunscreen)
2. primer (let it dry)
3. makeup (aka foundation)
4. setting powder (some women skip setting powder when using a primer)

There are primers that can substitute for foundation altogether. Smashbox Photo Finish Bronzing Primer has a sheer tint to it. You simply apply the primer and you're out the door. Similar to a tinted moisturizer, but with more perks.

Smashbox also makes color correcting primers. The colors are oh so subtle, but under foundation that's what we want.

What about the under eye area? I would skip primer on this area, unless you are using an extremely gentle, moisturizing formula like Sue Devitt Microquatic Fortifying Primer.

Sormé 's primer, called Fresh Start Under-Foundation Makeup Enhancer, contains witch hazel to help minimize pores, and glycerin to add moisture without oiliness. That's how it evens out the skin tone - it blots up excess oil produced by the skin during day, and hydrates the areas of the face that are dry.

If you've never used primer, start with any of the fine products here and see what it does for you. It may be a product that you use only for special occasions. If you find it easy and quick to use, adding it to your morning routine may be the way to get that flawless look.