Olivier Echaudemaison, Creative Director at Guerlain, says: "If you only use one beauty product on your eyes, go for mascara. Brown is perfect for daytime, and black for going out. Slightly more unusual colours such as pink, emerald green and electric blue are also an option for young women. If you're a bit more mature, they can make your pupils look dull and can look a bit trashy."
Finding the right one
Decide what you need most: volume, length, or curl. You can't get all three in one mascara, so choose carefully!
Be aware of optical effects:
> If you have fine lashes, use a lengthening mascara, but remember that the longer your lashes, the thinner they look, so go for a volumising one too!
> If you have short lashes, go for a volumising mascara and remember that the larger your lashes, the shorter they look, so go for a lengthening one too that separates your lashes out well (like a false-eyelash effect).
> If you have fairly ordinary lashes, go for a curling mascara so there's no need for eyelash curlers!
Waterproof mascara is great if you're going to be exercising or if your emotions could get the better of you on big occasions! Waterproof doesn't run when it comes into contact with tears or water, so you don't have to worry about panda eyes. However, don't use waterproofs all the time: like hair dye, they can damage your lashes.
The best ones to use are water-soluble mascaras (try Clarins or Benefits).