A Drow can see shades of red and white through darkvision (infravision). The brighter the red, the hotter the source, white results from very hot sources or real light that's not quite bright enough to make the drow shift into the regular spectrum. Here is an illustration of what the Drow actually sees with her eyes:

Because of the absence of light, several things are done differently by Drow than would be done by surface dwellers. First of all the heat sense allows a Drow to easily identify the state or arousal of another drow, as well as states of emotion. Furthermore a Drow can identify how long ago an object has been held or an area has been passed through based on its 'visual' temperature.

Mirrors:   There are extremely rare in the Underdark. Since mirrors relly on reflected light to work, such a device would be quite useless. Only in the presence of real light would the mirror show a reflection. Similarly, liquids don't show reflections, but are usually cooler than their surroundings.

Inks and writing:     A few minutes after a Drow writes a letter, the parchment and the ink become of a homogenous temperature and look blank. Wizards and Priestesses often use real light in the form of candles expressly for the purpose of reading scrolls or spell books. Special fluorescent inks are also available, however these are expensive and never last forever.

Faerie fire; dancing lights:     Faerie fire and dancing lights is one of the drow's innate abilities, the light produced by these sources is too faint to even read by however and in no way disrupts darkvision.

Darkness:     The special ability of all Drow is to create a globe of darkness, like with the wizard spell, even darkvision doesn't allow sight within the globe.

Hiding:     The usual ability to hide, assumes that you can hide in shadows, or out of site. The Drow have mastered a special form of hiding only possible in a lightless world. They can pick a spot in a cave wall that more closely matches the temperature of their clothing and blend in. Anyone else attempting to hide from a Drow would be spotted instantly even in the darkest corners.

Ranged Weapons:     There is little purpose in carrying a long ranged weapon in the underdark, first of all because most caverns wind long before maximum range, and second because drow darkvision only extends to 120 feet. Therefore the standard hand crossbow is the ranged weapon of choice.

Invisibility:     Invisibility cast by a Drow functions perfectly, masking even heat emanations. Invisibility cast by a surface dweller makes the caster invisible to a drow, but you can still see the warmer spots where the caster is standing on the ground.

Bright Light:     Bright light hurts the Drow's eyes and blinds them temporarily. It is often used as a weapon.