Good lighting is necessary to enable work to be done well and in comfort. A building with bad lighting is an inefficient building; however attractive it may look superficially, it will be judged a bad building by those who have to work in it. The practical result will be that work will be done badly, or slowly, or at the expense of the wellbeing of the occupiers, or all three. The appreciation of lighting depends on sight and intelligence, and the goodness of lighting can be assessed only in relation to what is known of vision and human psychology. Poor lighting can often be combated by good vision and keenness on the work, but at the eventual expense of comfort and efficiency.