On which place of your body do you match the foundation color? Usually gals test it on the neck, jaw, or inner wrist. But these places are not the best.. here is why.
If you match on your inner wrist, you are way wrong. The inner wrist has large veins and does not get sun light exposure. So the tone of the skin on your inner wrist cannot be compared with the one on your face.
The neck is not an ideal place either. Your head drops shadows on your neck and therefore it does not get enough sun light. The tone of skin on the neck also contains much less pigment than the the face.
Also, the jawline does not work for everybody. For some people, the jawline appears and causes different shadows that might be lighter or darker than the rest of the face. The difference is not huge, but why take risks ?
Beauty experts advice to test foundation on your chest just below the neck. This way your face will look consistent with the rest of your body. This of course assumes that your chest is usually exposed to sun light. If you are a conservative, you can match the color to the outer arm which is usually exposed to the sun in similar amounts as your face.