The Lake County Astronomical Society

A Short History of Lens Coating

In the early days of photography, exposure to air caused lenses to eventually acquire a sort of natural coating, referred to as "blooming". But rather than it being a detriment, photographers found that lenses afflicted with blooming had increased light transmission and better contrast, because the blooming reduced light scatter. As a result, old camera lenses were highly prized among photographers. Investigation of this phenomenon led to the development of artificial lens coatings, which do for our telescope equipment today what blooming did for old camera lenses, except to a much higher degree.