4/3/2023 0 Comments Absolute brightness![]() ![]() In art and design education, lightness (generally under the name "value" or "tone") is very often treated separately from and earlier than "colour" (meaning only hue and chroma) as one of the fundamental elements of composition, alongside line, shape, mass, rhythm etc. If the lightness information in an image is isolated from the chromatic information, remarkably large amounts of the legibility and compositional structure are preserved (Fig. In artworks and in perception of images in general, lightness is the pre-eminent attribute or dimension of colour (Fig. ![]() Value sketches of three of Howard Pyle's illustrations, from Andrew Loomis' Creative Illustration (1948). Here the finite range of brightnesses of the pixels (at a given brightness setting of the display) creates a context within which greyscale value is perceived.įigure 1.3.2. However, colours of luminous computer and television screens are seen as having greyscale value when the screen is perceived, as it normally is, as an illuminated page instead of as a primary light source. Primary light sources perceived as such can be compared as brighter or dimmer, but not as lighter or darker grey, and can not be said to have, for example, a middle grey value. Lightness does not apply to areas perceived as a primary light source because such areas are not judged relative to a definite upper limit perceived as being white. Notice that the phrase "of a similarly illuminated area" implies that the area being judged is also illuminated. All of these terms are most commonly applied to colours of objects seen as reflecting light, although the standard definition of lightness also allows for light-transmitting objects: Lightness: "brightness of an area judged relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting" ( CIE 2011, 17-680) where brightness is the amount of light perceived to be emitted or reflected by an area (see Section 1.6). Lightness, value and greyscale value all increase from black to white, while tone as used by painters (in this sense) is more often deemed to increase from white to black. The terms lightness, value, greyscale value and tone are all closely related or identical in meaning, and refer to the attribute or dimension of colour consisting of a scale between black and white through various shades of grey. B, lightness/value information and C, hue and chroma information. Sunlight Sweet, Coogee (1890) by Arthur Streeton. "Lightness", "Brightness" and "Value" in Digital Colour Spaces Lightness, Value, Greyscale Value and Toneįigure 1.3.1.Lightness, Value, Greyscale Value and Tone.Value, greyscale value, tone, lightness 1.3 The Dimensions of Colour: Lightness ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |