"Hi, I am Patricia Longo and I'm a celebrity make-up artist. I've worked with models from Sports Illustrated, like Brooklyn Decker and Julie Henderson to Alec Baldwin at 30 Rock. All those things that experts do that the average person doesn't know how to do will learn how to do it on these videos. Flawless Face: Foundation Primer People don't know why they wear foundation primer. Primer is actually the middle man, the middle man between your moisturizer and your foundation. So when you put on your moisturizer I always recommend putting it on at least twenty minutes before you do the rest of your makeup. That way your moisturizer sets and now you can put the primer on which basically separates the moisturizer from the foundation. If you don't use a primer, by the end of the day your foundation actually seeps into the moisture and once your moisturizer absorbs the foundation, it's pretty much gone. So that's why I recommend using a primer, it basically separates the two and keeps your foundation on a lot longer throughout the day. Now there are so many different primers out there, right Isabella? And you have to feel comfortable with which one fits more your skin. So if you have really oily skin, you don't want to use too heavy of a primer and I believe Laura Mercier makes one of the best primers out there. It's very good for all combination, dry, oily, whatever skin you have, this one really works. Then there are ones that are a little heavier and some that have shimmer in them. I'm going to go today with the Laura Mercier one. It comes in a tube and I put just a dimes size, very, very small, not a lot. And I put it on like moisturizer. So what I do is I dab it here and then what I do is I put it on the face, dabbing, on her T zone, on her cheeks. It gives a nice moist feeling on the skin. Doesn't it feel nice? Very soothing and light, it doesn't feel heavy, right? People always go ""How many layers do I have to have on my skin?"" But as long as you put the moisturizer on twenty minutes before the primer, it won't feel so gooky. And now I just blend it in, as if I were blending in my moisturizer and it seeps right into the skin. And once you have your primer on, you can immediately start with your foundation.