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| # Click on the Highlight Color pop-down menu and choose Other. | | # Click on the Highlight Color pop-down menu and choose Other. |
| # Select the CMYK Picker and set the values to 100% cyan, 100% magenta, and 100% yellow. They produce black, illustrating the subtractive nature of CMYK! | | # Select the CMYK Picker and set the values to 100% cyan, 100% magenta, and 100% yellow. They produce black, illustrating the subtractive nature of CMYK! |
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| + | =Color Spaces= |
| + | [[File:Colorspace.jpg|right]] |
| + | A color space is a model for representing color in terms of intensity values. A color space specifies how color information is represented. It defines a one, two, three, or four dimensional space whose dimensions, or components, represent intensity values. Visually, these spaces are often represented by various solid shapes, such as cubes, cones or polyhedra. |
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| + | ColorSync supports several different color spaces to give users the convenience of working in whatever kind of color data most suits their needs. For example, RGB space is a three-dimensional color space whose components are the red, green, and blue intensities that make up a given color. |
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| + | The ColorSync color spaces fall into several groups or base families. An additional color space, Hi-Fi color space, is primarily used in new printing processes involving the use of gold plate and silver, and also for spot coloring. |
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| + | ===Gray Spaces=== |
| + | Gray spaces typically have a single component, ranging from black to white. Gray spaces are used for black-and-white and grayscale display and printing. |
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| + | [[File:Greybttrfly.jpg]] |
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| + | [[File:Grayspace.jpg]] |
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| + | ===RGB-Based Color Spaces=== |
| + | [[File:Rgb.jpg|right]] |
| + | The RGB space is a three-dimensional color space whose components are the red, green and blue intensities that make up a given color. For example, scanners read the amounts of red, green, and blue light that are reflected from an image and then convert those amounts into digital values. Displays receive the digital values and convert them intro red, green, and blue light seen on screen. RGB color spaces are additive. |
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| + | RGB-based color spaces are the most commonly used color spaces in computer graphics, primarily because they are directly supported by most color displays. Because the colors produced by RGB specifications vary from device to device they are called device-dependent color spaces. Device-dependent color spaces enable the specification of color values that are directly related to their representation on a particular device. |
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| + | The groups of color spaces within the RGB base family include RGB spaces, HSV spaces and HLS spaces: |
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| + | '''RGB Spaces''' - any color expressed in RGB space is some mixture of three primary colors: red, green, and blue. |
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| + | '''HSV and HLS Spaces''' - transformations of RGB space that allow colors to be described in terms more natural to an artist. The name HSV stands for hue, saturation, and value. HLS stands for hue, lightness, and saturation. |
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| + | ===CMY-Based Color Spaces=== |
| + | [[File:Cmyk.jpg|right]] |
| + | CMY-based color spaces are most commonly used in color printing systems. They are device dependent and subtractive in nature. The groups of color spaces within the CMY family include: |
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| + | '''CMY''' - not very common except on low-end color printers. |
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| + | '''CMYK''' - models the way inks or dyes are applied to paper in printing. The name CMYK refers to cyan, magenta, yellow, and black. Cyan, magenta, and yellow are the three primary colors in this color space. Red, green and blue are the secondaries. Theoretically black is not needed. However, when full-saturation cyan, magenta, and yellow inks are mixed equally on paper, the result is usually a dark brown, rather than black. Therefore, black ink is overprinted in darker areas to give a better appearance. |
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| + | CMYK colors vary with printer, ink, and paper characteristics. In addition, different devices have different gamuts, or ranges of colors that they can produce. Because the colors produced by both RGB and CMYK specifications vary from device to device, they are called device-dependent color spaces. |
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| + | Conversion from an RGB color space to a CMYK color space involves a number of variables. It involves device-specific, ink-specific, and even paper-specific calculations of the amount of black to add in dark areas and the amount of other ink to remove where black is to be printed. ColorSync performs these calculations for the user when converting among color spaces. |
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| + | ===Device-Independent Color Spaces=== |
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| + | Device-Independent color spaces are used mainly for color models and by the system for translating between RGB & CMYK models. |
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| + | Every color monitor has its own range (or gamut) of colors that it can generate using its RGB phosphors - even monitors made in the same year by the same manufacturer. The same is true for printers and their CMYK colorants, which in general have a more limited gamut than most monitors. Because the colors produced by both RGB and CMYK specifications vary from device to device, they are called device-dependent color spaces. |
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| + | [[File:Di.jpg|left]] Some color spaces allow color to be expressed in a device-independent way - colors that are not dependent on any particular device. Device-independent colors, are meant to be true representations of colors as perceived by the human eye. These color representations, called device-independent color spaces, result from work carried out in 1931 by the Commission Internationale d'Eclairage (CIE) and for that reason are called CIE-based color spaces. |
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| + | The goal of the CIE was to create a repeatable system of color communication standards for manufacturers of paints, inks, dyes, and other colorants. |
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| + | These standard's most important function is to provide a universal framework for color matching. Device-independent color spaces are used for the interchange of color data from the native color space of one device to the native color space of another device. They represent the entire range of visible colors as translation spaces. This means that any color that is selected on a display is in the gamut of this neutral color space. |
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| + | [[File:Cielab.jpg|right]] CIE L*a*b* is a three dimensional color space that is based upon human perception of color. It is the most widely used of the CIE color spaces. L*a*b* color space is based on the theory that a color cannot be both green and red at the same time, nor blue and yellow at the same time. As a result single values can be used to describe the red/green and yellow/blue attributes. |
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| + | CIE L*a*b* space represents color relative to a reference white point, which is a specific definition of what is considered white light, usually based on the whitest light that can be generated by a given device. |
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| + | The CIE color spaces form the foundation of device-independent color for color management. |
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| =See Also= | | =See Also= |