Most Helpful Guy
Painters prefer to work with natural light but will accept a blend of natural, incandescent & fluorescent in some cases. It follows then that once you find the purest color/reflectivity in a mirror, you/it should benefit from similar lighting in order to get a true reflection.
Bathroom vs work lighting should be obvious in differences created by the light "bulbs", not to mention shadows, et al. ... not really candidates but easy to use. Cameras must be out of budget sorts in order to come close to a true mirror setting (above)
Most Helpful Girl
it has to do with lighting quality- the lights in your bathroom are different than those in your room. and none of them match up with the lighting outside.
if you are using a make-up mirror that magnifies, that's not how you are going to look to someone else. and your camera phone might be blurry.
there really is no right answer. it depends on how you look in different conditions.