Frosted glass
Frosted glass is the slang term for opaque white glass, a type of glass that is translucent but opaque. Cloudy glass is an opaque, milky white glass.
Types of frosted glass:
- Glass colored by adding an opacifying substance
- , partially opaque made by roughening the surface of glass as Frosted glass designated
- Milk engaging over glass , a composite of a transparent layer with a white glass
Turbidity due to admixture
The addition of calcium phosphate , fluorides or tin oxide before melting causes the glass to become cloudy. This is often bone ash has been used, from which the term Beinglas derived to describe this type of glass. Frosted glass, which is created by adding cryolite - a fluoride - is also called cryolite glass .
Cloudiness due to roughening
The surface of the glass is roughened either by acid etching or by sandblasting . The result is a surface like a screen . The light that passes through is scattered by the rough surface . This makes the glass appear whitish and cloudy.
Roughened glass is sensitive to fingerprints and dirt. In order to smooth the surface, it can be coated or mechanically processed. This type of frosted glass is also known as frosted glass .
Applications, alternatives
A cloudiness caused by roughening the surface does not have as strong a scattering effect as a milky cloudiness in the substance. The effect of the roughness of the surface can be significantly reduced by wetting it with water or oil; the valleys in the glass ( refractive index approx 2/3 ironed out. In lighting technology for photography and film, surface-structured or opaque plastic films, parchment paper or translucent fabrics that are unbreakable, light and foldable are also used as cloudy surfaces.
With the light source of the simple tungsten filament light bulb, a certain opacity is achieved by matting the inside of the bulb, but a greater degree by means of an opaque inside coating with scattering powder. Fluorescent tubes are matted at the same time by the fluorescent powder adhering to the inside, tube screens by printed phosphors.
The capillary of a liquid thermometer, which is filled with red or blue colored alcohol, is often made of frosted glass for high-contrast readability. Luminaires that should appear very evenly bright are made of opaque milk glass, often spherical, but this also absorbs a certain proportion of the light. Rather only small flat surfaces, for example in railway switch signal cubes, are or were made of frosted glass in sheet metal frames, larger surfaces today are often made of opaque acrylic glass, which is lighter and more impact-resistant.
See also
literature
- Frosted glass . In: Meyers Konversations-Lexikon . 4th edition. Volume 11, Verlag des Bibliographisches Institut, Leipzig / Vienna 1885–1892, p. 611.
- Frosted glass . In: Der Grosse Herder , 6th 5th edition. Freiburg 1955, Col. 521
Web links
- How is glass made? Children's university on the net; Retrieved February 26, 2006