Just like how you shouldn’t judge a book by its cover, you should not judge a foundation by the color in the bottle. Chances are, it will turn a tad darker on your skin, and unless it’s opaque, the redness/tan/yellowness of your skin will show through the foundation, making the color slightly different. Oh, and there’s oxidation, where due to the chemistry between your skin and foundation, it may look 2 shades darker after a couple of hours. Lovely, eh? Now you know why it’s so difficult to find the perfect foundation. The word on the street is that the oil in your skin makes foundation oxidize and become darker, and primers help it to stay the same, so I decided to test if that’s true.
Since you usually wear foundation during the day and you should ALWAYS wear spf (makeup does not give you enough spf), I tested different foundation on moisturized skin, moisturized+primed skin, and moisturized+oiled skin. I did two batch, the base of the first batch are: Murad Essential + C Day Moisture spf30, Murad spf30 + Clarins Instant Smooth primer, and Murad spf30 + Tarte Maracuja oil. The foundations I tested are: Guerlain Lingerie de Peau foundation, USL Touch Eclat, and MUFE ProFinish powder.
Interestingly the effect of oxidation is more obvious with powder, where you can obviously see it being darker in the image. The effect on liquid foundation are more subtle, where the swatch over primer is just a tiiiiny bit lighter, but unless you cake it on, I doubt you would be able to tell on the face.
To confirm the result, I then tried it with 3 different base and 3 different foundation. The base I used this time are: Benefit Triple Performing Emulsion SPF15, Benefit spf15 + Nude ProGenius oil, Benefit spf15 + Hourglass no.28 primer. The foundations being tested this time are: Benefit Hello Flawless, Urban Decay Naked, and Shiseido powder.
I applied oil to the middle column instead of the last column this time, but just as expected, the powder foundation oxidized and became darker when applied over the area moisturized with oil. There isn’t much difference for the liquid foundation, neither of which seem to have oxidized at all when applied over oil.
So, it seems that oxidation does happen when it comes to oily skin, but it depends on the foundation and since most people apply them to be sheer/med coverage, it’s not really noticeable. And primers do help, as long as you use the ones that are right for your skin type (hydrating primer for dry skin, mattifying primer for oil skin etc). I am surprised at how the powder foundations got so much darker, that was rather unexpected. Anyways, it’s just a fun little experiment since I’ve got so many samples from my quest to find a foundation in my shade.