Recommended Light Levels
The amount of light needed for any situation or task varies, and depends on:
The units that we use to measure the amount of light that falls on any given surface, is called "Lux". The light is usually measured about 78 cm from the floor (table height) unless special circumstances demand a different approach.
The following is a chart of recommended light levels in various situations. These are general recommendations, and can/should be adjusted for the situation at hand.