How its Made
Photographs
Fur Tanning
Welding Electrodes
Electric Violins Full Episode
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Photographs
A photograph or photo is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic image such as a CCD or a CMOS chip. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating photographs is called photography. The word "photograph" was coined in 1839 by Sir John Herschel and is based on the Greek φῶς (phos), meaning "light", and γραφή (graphê), meaning "drawing, writing", together meaning "drawing with light".
Fur Tanning
Tanning is the process of treating skins of animals to produce leather, which is more durable and less susceptible to decomposition. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name (tannin is in turn named for an old German word for oak or fir trees, which supplied it). Coloring may occur during tanning. A tannery is the term for a place where the skins are processed.
Tanning leather involves a process which permanently alters the protein structure of skin. Making "rawhide" (untanned but worked hide) does not require the use of tannin. Rawhide is made by removing the flesh and fat and then the hair by use of an aqueous solution (this process is often called "liming" when using lime and water or "bucking" when using wood ash (lye) and water), then scraping over a beam with a somewhat dull knife, then drying. The two aforementioned solutions for removing the hair also act to clean the fiber network of the skin and allow penetration and action of the tanning agent, so that all the steps in preparation of rawhide except drying are often preludes to the more complex process of tanning and production of leather.
Welding Electrodes
In arc welding an electrode is used to conduct current through a workpiece to fuse two pieces together. Depending upon the process, the electrode is either consumable, in the case of gas metal arc welding or shielded metal arc welding, or non-consumable, such as in gas tungsten arc welding. For a direct current system the weld rod or stick may be a cathode for a filling type weld or an anode for other welding processes. For an alternating current arc welder the welding electrode would not be considered an anode or cathode.
Electric Violins
An electric violin is a violin equipped with an electronic output of its sound. The term most properly refers to an instrument purposely made to be electrified with built-in pickups, usually with a solid body. It can also refer to a violin fitted with an electric pickup of some type, although "amplified violin" or "electro-acoustic violin" are more accurate in that case.
Electrically amplified violins have been used in one form or another since the 1920s; jazz and blues artist Stuff Smith is generally credited as being one of the first performers to adapt pickups and amplifiers to violins. The Electro Stringed Instrument Corporation, National and Vega sold electric violins in the 1930s and 1940s; Fender produced a small number of electric violins in the late 1950s. There has been a great deal more commercial success of well known manufacturers of electric violins since the 1990s for both well known, established companies and new makers too.
Acoustic violins may be used with an add-on piezoelectric bridge or body pickup, or a magnetic pickup attached to the fingerboard end. Alternatively, an electrodynamic pickup can be installed under an acoustic violin's fingerboard avoiding interference with any tone-producing parts of the violin, and so keeping its acoustic resonances and tone intact.
