The light whose wavelength (about 380 nanometers) is just long enough not to be x-rays, but just enough shorter than violet light so that it is not visible to the human eye. Ultraviolet is also known by the short form of "UV." It is sometimes called black-light because ultraviolet lamps (usually a mercury-vapor lamp) appear quite dark even when lit, and because of the peculiar way it illuminates certain kinds of surfaces, such as day-glo colors.Various colors of paint and layers of varnish fluoresce in different ways under UV light. This fluorescence can be photographed, both in color and in black and white. Recently applied paint absorbs UV and appears dark, allowing for the detection of areas of inpainting. Aged retouching, however, often goes undetected with UV. Examination under UV can sometimes also help in identifying pigments.Also see angstrom, color, sight, and spectrum.

Your data and time are valuable. There's a new web browser that considers your time and security as a top priority.

Download Brave Browser For Free!

Brave uses the latest in blockchain technology.

This ensures a higher quality and more secure experience. Learn more about this fantastic breakthrough.

Loads Content Up To 8X Faster

Because Brave blocks unwanted tracking scripts that run in the background, your browsing speed will be unparalleled.

Ultimate in Privacy & Security

Brave fights malware and prevents tracking, keeping your information safe and secure.