This reminds me of the age-old question, "Which came first; the chicken or the egg?" While there is no one right or wrong answer, get my thoughts on the topic — and be sure to share yours in the comments — when you read more.
Concealer before foundation:
- When it works: If you aren't one to wear a full face of foundation or you really don't need much coverage, start off with an application of concealer or corrector on areas that need it the most. Follow up with foundation only where necessary. (You might find that you hardly need any foundation at all.) Another benefit of applying concealer first is that the foundation can actually help blend away an obvious corrector or concealer lines of demarcation.
- Other things to think about: If you're using a cream-to-powder formula, always do the concealer first to avoid blending disasters, and if you do have lots of concealing to do (under the eyes for example), go with a combo of concealer first, then foundation, and then more concealer if needed. A downfall of pre-concealing? Concealer that's applied first can shift around when foundation is used on top of it.
Concealer after foundation:
- When it works: While you should go with what works for you, this is my preferred method. First start out with the thinnest veil of foundation possible to even out the skin tone and provide coverage, blending in product only where needed. Then add concealer sparingly to hone in on areas that need extra camouflaging for the most natural effect. Applying concealer post-foundation is also a great way to clean up minor makeup spills.
- Other things to think about: Concealing over foundation can be hard to blend, but using light, feathery strokes and the proper brushes (I like Bare Escentuals' Precision Concealer Brush) on the outer edges of the concealer can make it all the more seamless.