A daylight lamp is term used by marketers to describe lights that are meant to mimic the properties of actual sunlight. They are often referred to as full-spectrum lights, but although they generally produce light throughout the spectrum, they often do not have an even distribution of light over that spectrum. In fact, a consumer daylight lamp may often differ only slightly from an ordinary bulb. Different people choose to use a daylight lamp for different reasons.
Gardeners may use a daylight lamp to help plants grow in regions that may receive insufficient light, or during times of year when not enough light is available. These lamps can be used to ensure winter crops, even for plants that ordinarily have a short growing period. Good daylight lamps are generally significantly more expensive than ordinary lights, so their use tends to be limited to those plants where the value makes the added expense worthwhile. For example, they may be used for valuable flowers such as orchids, and may also be cost effective for other plants, such as high-cost food crops, or other high-cost plants, such as marijuana.
Other times they are used by artists, who may use them while painting to ensure the paintings look the way they will look on a wall. Most artists prefer to work with northern light, as this mimics the natural light most people set up in their homes or galleries to present paintings. In cases where northern light is not available, either because of the position of the studio, the time of year, or the time of day, a daylight lamp may be used instead to mimic as closely as possible the way the painting will look when hung.
The lack of natural light during the winter months in northern climates may provoke a depression, commonly referred to as seasonal affective disorder (SAD). Because sunlight helps regulate the body’s natural circadian cycles, and stimulates the production of important chemicals in the body, when it is not present in sufficient quantities - people may find themselves experiencing depressive states. A daylight lamp can be used in these cases to help replace natural daylight, and stave off seasonal affective disorder. Daylight lamps may also be used to regulate the circadian cycle, and help minimize the effects of jetlag.
There are other uses of artificial daylight as well. For example, a number of people have proposed that using the proper spectrums of light in refrigerators could help stimulate fruits and vegetables to photosynthesize, and help prolong their period of freshness, as well as helping them to retain their nutritional value. A number of modern refrigerators have begun to utilize these lights as a result, although there have been no formal studies into its efficacy.
A variation of the daylight lamp can be found in many tanning beds. Fluorescent lights are used to simulate the UV content of the sun. This produces a cosmetic tan, but also brings the negative effects of UV radiation. This includes an increased chance of skin cancer.