I tried using a primer underneath my EDM foundation today for the first time, and WHAT a difference. Normally, I can get a pretty good finish at the beginning of the day: relatively matte, even, and full-coverage without looking cakey. But introduce any amount of heat (leading to sweat haha) or my extremely oily skin within a few hours, and it starts towards a disaster. Try oil slicks, extreme caking, smudging, melting, creasing, and wearing-off on blemishes. By the end of the day, it's just a mess (this is due to me or the weather, not the makeup). It would take constant blotting (every 20-30 minutes) to prevent this, which is just a pain.
Going on to today: Applied Smashbox Photo Finish Primer before applying my foundation. It only took about half as much product to create the same, airbrush finish while maintaining a good amount of coverage for flawless skin. Already impressed, I set out, still expecting the worst for my mid-day checkup. After about 4 hours, I hesitantly made my way to the mall restroom, and took a look under the harshness of the fluorescent lights. Now, mind you, this had been after walking around in 90 degree heat, sweating up a storm, with mild blotting of my face with back of my hand: not a good recipe for flawless makeup. But lo and behold, almost nothing had changed since that morning. A bit of creasing in the "smile lines" (parentheses), and that was it. I was amazed. No shininess, no oil slicks, no color change... And all thanks to a primer. Even now, more than 12 hours after the original application, only a very mild shine (and absolutely no blotting during the day), more akin to a "satin" finish, and still no more creasing than I had seen around 1 earlier today.
So in conclusion, a primer before mineral powder foundation (at least for me), keeps oil completely at bay, prevents color change, decreases amount of product used in application, and prevents caking and smudging. Overall, a good deal for a simple, quick extra step.
