RAL colour standard

RAL is a colour matching system used in Europe. In colloquial speech RAL refers to the RAL Classic system, mainly used for varnish and powder coating but nowadays there are reference panels for plastics as well. Approved RAL products are provided with a hologram as of early 2013 to make unauthorised versions difficult to produce. Imitations may show different hue and colour when observed under various light sources.

RAL colour space system

RAL Classic

In 1927 the German Reichs-Ausschuß für Lieferbedingungen und Gütesicherung (State Commission for Delivery Terms and Quality Assurance) invented a collection of 40 colours under the name of "RAL 840". Prior to that date manufacturers and customers had to exchange samples to describe a tint, whereas from then on they would rely on numbers.

In the 1930s the numbers were changed uniformly to four digits and the collection was renamed to "RAL 840 R" (R for revised). With tints constantly added to the collection, it was revised again in 1961 and changed to "RAL 840-HR", which consists of 210 colors and is in use to this day. In the 1960s the colours were given supplemental names to avoid confusion in case of transposed digits.

Color space

A color space is a specific organization of colors. In combination with physical device profiling, it allows for reproducible representations of color, in both analog and digital representations. A color space may be arbitrary, with particular colors assigned to a set of physical color swatches and corresponding assigned names or numbers such as with the Pantone system, or structured mathematically, as with Adobe RGB or sRGB. A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers (e.g. triples in RGB or quadruples in CMYK); however, a color model with no associated mapping function to an absolute color space is a more or less arbitrary color system with no connection to any globally understood system of color interpretation. Adding a specific mapping function between a color model and a reference color space establishes within the reference color space a definite "footprint", known as a gamut, and for a given color model this defines a color space. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB color model. When defining a color space, the usual reference standard is the CIELAB or CIEXYZ color spaces, which were specifically designed to encompass all colors the average human can see.

Glossary of chess

This page explains commonly used terms in chess in alphabetical order. Some of these have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of chess-related games, see Chess variants.

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[adjective: prophylactic] Prophylactic techniques include the blockade, overprotection, and the mysterious rook move.

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References

Bibliography

Space (mathematics)

In mathematics, a space is a set (sometimes called a universe) with some added structure.

Mathematical spaces often form a hierarchy, i.e., one space may inherit all the characteristics of a parent space. For instance, all inner product spaces are also normed vector spaces, because the inner product induces a norm on the inner product space such that:

where the norm is indicated by enclosing in double vertical lines, and the inner product is indicated enclosing in by angle brackets.

Modern mathematics treats "space" quite differently compared to classical mathematics.

History

Before the golden age of geometry

In the ancient mathematics, "space" was a geometric abstraction of the three-dimensional space observed in the everyday life. Axiomatic method had been the main research tool since Euclid (about 300 BC). The method of coordinates (analytic geometry) was adopted by René Descartes in 1637. At that time, geometric theorems were treated as an absolute objective truth knowable through intuition and reason, similar to objects of natural science; and axioms were treated as obvious implications of definitions.

Five-dimensional space

A five-dimensional space is a space with five dimensions. If interpreted physically, that is one more than the usual three spatial dimensions and the fourth dimension of time used in relativitistic physics. It is an abstraction which occurs frequently in mathematics, where it is a legitimate construct. In physics and mathematics, a sequence of N numbers can be understood to represent a location in an N-dimensional space. Whether or not the actual universe in which we live is five-dimensional is a topic of debate.

Physics

Much of the early work on five dimensional space was in an attempt to develop a theory that unifies the four fundamental forces in nature: strong and weak nuclear forces, gravity and electromagnetism. German mathematician Theodor Kaluza and Swedish physicist Oskar Klein independently developed the Kaluza–Klein theory in 1921, which used the fifth dimension to unify gravity with electromagnetic force. Although their approaches were later found to be at least partially inaccurate, the concept provided a basis for further research over the past century.

RAL

RAL may refer to:

System (typeface)

System is a family of proportional raster fonts distributed with Microsoft Windows. The font family contains fonts encoded in several Windows code pages, with multiple resolutions of the font for each code page. Fonts of different code pages have different point sizes. Under DBCS Windows environment, specifying this font may also cause application to use non-System fonts when displaying texts.

In Windows 2000 or later, changing script setting in some application's font dialogue (e.g.: Notepad, WordPad) causes the font to look completely different, even under same font size. Similarly, changing language setting for Windows applications that do not support Unicode will alter the appearance of the font.

When Windows is running with low system resources, System is the fallback font used for displaying texts.

Example

The following is an example of the System typeface.

See also