Bitumen of Judea, or Syrian asphalt, is a naturally occurring

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

that has been put to many uses since ancient times.

Wood coloration usage

Bitumen of Judea may be used as a colorant for wood for an aged, natural and rustic appearance. It is soluble in

turpentine Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthene, terebinthine and (colloquially) turps) is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Mainly used as a spec ...

and some other

terpenes Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes ar ...

, and can be combined with oils, waxes, varnishes and glazes.

Light-sensitive properties

It is a light-sensitive material in what is accepted to be the first complete

photographic process A list of photographic processing techniques. Color *Agfacolor **Ap-41 process (pre-1978 Agfa color slides; 1978-1983 was a transition period when Agfa slowly changed their color slide films from AP-41 to E6) *Anthotype *Autochrome Lumière, 1903 ...

, i.e., one capable of producing durable light-fast results. The technique was developed by French scientist and inventor

Nicéphore Niépce Joseph Nicéphore Niépce (; 7 March 1765 – 5 July 1833), commonly known or referred to simply as Nicéphore Niépce, was a French inventor, usually credited with the invention of photography. Niépce developed heliography, a technique he us ...

in the 1820s. In 1826 or 1827, he applied a thin coating of the tar-like material to a

pewter Pewter () is a malleable metal alloy consisting of tin (85–99%), antimony (approximately 5–10%), copper (2%), bismuth, and sometimes silver. Copper and antimony (and in antiquity lead) act as hardeners, but lead may be used in lower grades ...

plate and took a picture of parts of the buildings and surrounding countryside of his estate, producing what is usually described as the first photograph. It is considered to be the oldest known surviving photograph made in a camera. The plate was exposed in the camera for at least eight hours. The bitumen, initially soluble in spirits and oils, was hardened and made insoluble (probably

polymerized In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many for ...

) in the brightest areas of the image. The unhardened part was then rinsed away with a solvent. Niépce's primary objective was not a

photoengraving Photoengraving is a process that uses a light-sensitive photoresist applied to the surface to be engraved to create a mask that protects some areas during a subsequent operation which etches, dissolves, or otherwise removes some or all of the mat ...

or photolithography process, but rather a photo-etching process since engraving requires the intervention of a physical rather than chemical process and lithography involves a grease and water resistance process. However, the famous image of the Cardinal was produced first by photo-etching and then "improved" by hand engraving. Bitumen, superbly resistant to strong acids, was in fact later widely used as a

photoresist A photoresist (also known simply as a resist) is a light-sensitive material used in several processes, such as photolithography and photoengraving, to form a patterned coating on a surface. This process is crucial in the electronic industry. ...

in making printing plates for mechanical printing processes. The surface of a

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

or other metal plate was coated, exposed, developed with a

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

that laid bare the unexposed areas, then etched in an acid bath, producing the required surface relief.Beaumont Newhall, "The History of Photography," 2001, p 14.

References

Photographic processes dating from the 19th century {{photography-stub