Subtractive Light Filter
Subtractive Light Filter
a type of selective absorption light filter. Colored materials, such as glass, films, and layers of liquids, are used for selective absorption of radiation in any single region of the visible spectrum. The color of each filter is complementary to the color of the light it absorbs. Filters that absorb in the blue region of the spectrum are colored yellow; green-absorbing filters are purple, and red-absorbing filters are azure.