Colors are wavelengths on the electromagnetic spectrum. White is all colors, and black is absence of all color and of all light.

Vampires tend to not mind white because, I hypothesize, that it's not a particular color so it doesn't have all of its energy in one place, thus not giving off too much energy.
Vampires tend to like black because it doesn't give off energy, being that it's not a color.
Vampires typically don't like to be struck with high energy in the form of sunlight or bright colors [other than white] because, I hypothesize, it's difficult to dumb down the affect of a strong energy source that stays just as strong all the time.

Flashing lights [such as fluorescent lights] blare strong energy strikes each time the light flashes. The flickering of fire doesn't bother vampires because it's weaker energy or because the energy in nature is neutral.

Vampires are affected by energy strikes because when a vampire has too much energy, the balance of energies [stored in the chakras??] gets thrown off, short-circuiting him/her.

When Outdoors

A. Wear white or a less potent shade like antiqued-white, adding only small designs [polkadots, lace, etc.] that are black if you need to off-set the white. Sunlight is absorbed the least into the color white.
B. Walk under a lace umbrella or an umbrella with dangling tassels [any kind of decorative umbrella] to not only keep out the sun’s rays but also the rays from the sun that are reflected off of other objects. I recommend a white umbrella.

When Indoors

A. Keep your windows covered [black velvet curtains work best]
B. Use candles [that you make yourself or that you know are free of chemicals] and a fireplace or a wood-burning stove to provide lighting