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Anwendung von Farbsystemen in der Architektur
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9, 10 RAL-Design-Farbsystem 11 CIE-Farbraum 12 Lage der wichtigsten Farbräume im CIE-Farbraum 13 Farbtemperaturspektrum
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9, 10 RAL design colour system 11 CIE colour space 12 Location of most important colour spaces in CIE colour space 13 Colour temperature spectrum
Colour is a natural phenomenon, the product of the refraction, reflection and absorption of light. As such, it is a genetic factor in the origin and diversification of life on earth. The entire environment is a colour system that guarantees the survival of innumerable species. The creation of pigments in the plant world serves not only the process of photosynthesis and thus the growth of organisms; it is also a means of orientation for innumerable forms of life. Our sense of the beauty of natural colours is thus based on an intuitive understanding of a system of symbols that provide a means of communication for more than 20 million species; and man is constantly transforming and extending this natural order through the colour design of his cultural realm. This, in turn, reflects social needs for orientation, repulsion, attraction, disguise, identity, behavioural control and socio-cultural communication. Down to the age of globalization, colour design relied on natural material resources and pigments. For buildings of special importance valuable substances were often imported, a fact that manifests itself in the different coloration of public and private realms. We orient ourselves almost entirely according to facade coloration. The social order of premodern societies, therefore, is reflected not just in the formal stock of materials and their use in the public domain, but also in the coloration of architecture. Colour facilitates differentiation, categorization and identification. A systematic specification of colour tones, however, emerged only with industrialization. The discovery of synthetic pigments played a major role in the birth of the chemical industry, which today produces more than nine million tonnes of colorants. The development of global chemical concerns began with patents for synthetic substances, which revolutionized the appearance of our living environment and of consumer goods worldwide. As early as 1914, the German Nobel laureate Wilhelm Ostwald was researching a colour system that could be applied in architeture and industry. The “double cone” named after him is still the basis of many colour systems today (ill. 2). The industrialization of all realms of life calls for internationally recognized colour standards, the
development of which began at the beginning of the 20th century. The most important colour collection for architecture is still the RAL Classic, which was introduced in 1927 and today contains 213 standardized colour tones. The leading international colour collection in the field of printing is the Pantone Colour Matching System, the 1,755 special shades of which considerably extend the CMYK model. Pantone colour collections are available in the form of fans, books and loose-leaf ring files. Today, they are increasingly aimed not just at graphic artists but at product designers and even interior designers. Alternatively, in Europe, HKS colour fans and books are widely used. Le Corbusier recognized the effectiveness of colour in Modern Movement architecture when he stated that it is as powerful an element as a layout plan or section. Polychromy, he went on to say, is in fact a component of the layout plan and section. His ”Polychromie Architecturale”, newly compiled by Arthur Rüegg, contains not only an impressive documentation of Le Corbusier’s colours, but also the underlying theory and system of their application. Le Corbusier’s approach was based on his own form of abstract painting, in which colours were used not naturalistically, but as a field for experimentation in human perception. He believed that they could lend expression to a concept; they were a tool for the tectonic shaping of space, articulating it for the observer according to harmonic principles. Each of the colour collections, which he describes as a keyboard of harmonious tones, is assigned a specific theme such as space, sky, velvet, wall, sand, landscape and miscellaneous. For Le Corbusier, it was important that the overall composition should remain harmonically and thematically distinct in all constellations (ills. 4, 5). He implemented his system in the Villa La Roche (ill. 7). This tool can be applied systematically and was conceived for architects who have no basic education in painting and who have not come to terms with many aesthetic, tectonic and semantic effects of colour in space. The systematization of colours is oriented to three properties: hue, brightness and saturation. All colour systems are based on three-
dimensional coordinates, the axes of which follow a principle of polarities or opposites. Depending on the purpose, spherical, cubic, conical and rhombohedral forms are used. On the brightness scale, light and dark (black and white) are opposed to each other. On the saturation scale, a grey tone is opposed to a colour tone. The colour scale is frequently depicted in the form of a circle in which the physiologically determined primary colours yellow and blue, red and green form complementary opposities. Any number of mixed tones are possible with these scales based on a principle of equal spacings. At the centre is usually a medium, uncoloured grey tone that darkens to black or lightens to white. The two most important colour systems for architecture, urban planning, design, crafts, building authorities and conservation are the RAL Design System and the Natural Colour System (NCS). The RAL Design System consists of a scale of 1,625 tones that are evenly spaced colorimetrically according to the CIELab colour space. This can be simply read by colorimeters and is today an industrial standard (ills. 8 –10). The Natural Colour System is based on the Ostwald double cone, which consists of a series of coloured triangles (ill. 6). The NCS colour space comprises 1,950 tones and is available in the form of fans, a colour chart and a colour atlas. For practical reasons, all colour systems omit various qualitative properties such as luminance, intensity, transparency, etc. This, in turn, reduces their validity in architecture. As a result, surface appearance, tokens of ageing, scale, etc. as well as physical factors such as reflection, transmission and absorption of light cannot be apprehended. In 1931, the mathematical definition and measurement of technically functional colour space by the International Commission on Illumination (CIE) led to the establishment of a CIE standard valency system, which, with certain revisions, is still valid today. Colorimetry is the discipline of measuring the perceptible colour space by generalizing perceptions of colour stimuli and defining them according to their chromaticism. Today, the measurement of colour valencies is achieved on the basis of