Holophane is one of the oldest of lighting-related
products in the world; founded in 1898 in London, England.
They are a UK (based in Milton Keynes, England)
and US manufacturer (based in Newark, Ohio) of lighting
fixtures for commercial, industrial, outdoor, and
emergency applications. The hallmark of their products
is a glass reflector/refractor.
The hallmark of Holophane luminaires, or lighting fixtures,
is the borosilicate glass reflector/refractor. The glass
prisms provide a combination of uplight and downlight to
illuminate any environment evenly without creating
dark spots or glare. This ribbed glass shade/reflector,
called "Holophane" or "Holophane style/type" is iconic
in "vintage" style lighting, and is licenced and copied
throughout the lighting industry.