Having a Brighter World
It is difficult and depressing to stay in the dark. For this reason, we have windows and skylights to let the sunshine in during the day and lighting fixtures to brighten up our living and working spaces when the sun goes down. Illumination can make life more comfortable and more convenient. Nearly all tasks require light for their completion. Even a darkroom where photos are processed is equipped with a safelight that allows a photographer to properly execute his work.
Illumination, particularly in the evening, used to be provided by gas lighting, candles, and oil lamps. Today, these types of lighting are considered secondary sources of light as homes and offices shift to electric lighting. Man-made lighting keeps the world sufficiently illuminated even during the darkest of nights.