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This is a list of sources of light, the visible part of the electromagnetic spectrum.Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that ...
Entoptic images have a physical basis in the image cast upon the retina. Hence, they are different from optical illusions, which are caused by the visual system and characterized by a visual percept that (loosely said) appears to differ from reality.
The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire , from ancient campfires to modern kerosene lamps . With the development of electric lights and power systems , electric lighting has effectively replaced firelight.
Properties of natural or artificial light that may abnormally affect people include: Timing of light (upset of normal circadian rhythms, seasonal affective disorder, sleep disorders) Intensity of light (photophobia, sunburn, skin cancer) [1] [2] [3] Wavelength of light (in lupus, urticaria) Rapid flickers in intensity of light may trigger or ...
[9] [3] Photomultiplier tubes have been used to measure biophoton emissions from fish eggs, [10] and some applications have measured biophotons from animals and humans. [ 11 ] [ 12 ] [ 13 ] Electron Multiplying CCD (EM-CCD) optimized for the detection of ultraweak light [ 14 ] have also been used to detect the bioluminescence produced by yeast ...
Color temperature for white light sources also affects their use for certain applications. The color temperature of a white light source is the temperature in kelvins of a theoretical black body emitter that most closely matches the spectral characteristics (spectral power distribution) of the lamp. An incandescent bulb has a color temperature ...
Photographic lighting refers to how a light source, artificial or natural, illuminates the scene or subject that is photographed; put simply, it is lighting in regards to photography. Photographers can manipulate the positioning and the quality of a light source to create visual effects , potentially changing aspects of the photograph such as ...
Bioluminescence differs from biofluorescence in that it is the natural production of light by chemical reactions within an organism, whereas biofluorescence and biophosphorescence are the absorption and reemission of light from the natural environment.