Ekta Space

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The CIE color space chromaticity diagram. The outer curved boundary is the spectral (or monochromatic) locus, with wavelengths shown in nanometers. Note that the image itself describes colors using sRGB, and colors outside the sRGB gamut cannot be displayed properly. Depending on the color space and calibration of your display device, the sRGB colors may not be displayed properly either. This diagram displays the maximally saturated bright colors that can be produced by a computer monitor or television set. CIExy1931.png
The CIE color space chromaticity diagram. The outer curved boundary is the spectral (or monochromatic) locus, with wavelengths shown in nanometers. Note that the image itself describes colors using sRGB, and colors outside the sRGB gamut cannot be displayed properly. Depending on the color space and calibration of your display device, the sRGB colors may not be displayed properly either. This diagram displays the maximally saturated bright colors that can be produced by a computer monitor or television set.

The Ekta Space is a common name for two color spaces developed by Joseph Holmes - Ekta Space PS 5 and Ektachrome Space to safely contain fine image scans of film originals generally of 24-bit color depth.

Color space standard that defines a specific range of colors

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 color names or numbers such as with the Pantone collection, or structured mathematically as with the NCS System, Adobe RGB and sRGB. A "color model" is an abstract mathematical model describing the way colors can be represented as tuples of numbers ; 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.

Joseph E. Holmes is a color, natural light, landscape photographer from California. He is an innovator in the field of inkjet fine art print making, and has developed his own visual calibration software.

Ektachrome Brand name of a Kodak film

Ektachrome is a brand name owned by Kodak for a range of transparency, still, and motion picture films previously available in many formats, including 35 mm and sheet sizes to 11×14 inch size. Ektachrome has a distinctive look that became familiar to many readers of National Geographic, which used it extensively for color photographs for decades in settings where Kodachrome was too slow. Ektachrome is able to take photos at shutter speeds of 1/10,000 of a second without filters.

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Specification

RGB working spaces are ICC profiles, which encompass a particular region of the CIE XYZ color space (and therefore also the CIE L*a*b* color space). The function of ICC profiles is to establish an equivalence between device color values, such as RGB or CMYK, and actual colors, as represented by points in one of the CIE spaces. Given two ICC profiles, e.g. one for a working space and one for a printer, image files can be converted from one to the other, with good fidelity. This is a major part of color management.

RGB color space any additive color space based on an RGB color model

An RGB color space is any additive color space based on the RGB color model. A particular RGB color space is defined by the three chromaticities of the red, green, and blue additive primaries, and can produce any chromaticity that is the triangle defined by those primary colors. The complete specification of an RGB color space also requires a white point chromaticity and a gamma correction curve. As of 2007, sRGB is by far the most commonly used RGB color space.

ICC profile file format that characterizes a color input or output device

In color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium (ICC). Profiles describe the color attributes of a particular device or viewing requirement by defining a mapping between the device source or target color space and a profile connection space (PCS). This PCS is either CIELAB (L*a*b*) or CIEXYZ. Mappings may be specified using tables, to which interpolation is applied, or through a series of parameters for transformations.

The CIE 1931 color spaces were the first defined quantitative links between distributions of wavelengths in the electromagnetic visible spectrum, and physiologically perceived colors in human color vision. The mathematical relationships that define these color spaces are essential tools for color management, important when dealing with color inks, illuminated displays, and recording devices such as digital cameras.

An important consideration in selecting and using a space is to avoid clipping and to ensure that conversion into future output spaces is feasible.

Clipping, in the context of computer graphics, is a method to selectively enable or disable rendering operations within a defined region of interest. Mathematically, clipping can be described using the terminology of constructive geometry. A rendering algorithm only draws pixels in the intersection between the clip region and the scene model. Lines and surfaces outside the view volume are removed.

History

The purpose of these color spaces was to protect an image's actual colors (as scanned from film or as mapped from a color negative). One issue was handling the clipping process which is required when an out-of-range color is scanned.

J. Holmes designed Ektachrome Space in September 1997 and later its sister Ekta Space PS 5. It was the first RGB working space to be input-centric by design.


Related Research Articles

RGB color model additive color model based on combining red, green, and blue

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Web colors are colors used in displaying web pages on the World Wide Web, and the methods for describing and specifying those colors. Colors may be specified as an RGB triplet or in hexadecimal format or according to their common English names in some cases. A color tool or other graphics software is often used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#). A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified.

Gamut color reproduction

In color reproduction, including computer graphics and photography, the gamut, or color gamut, is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a certain output device.

In digital photography, computer-generated imagery, and colorimetry, a grayscale or greyscale image is one in which the value of each pixel is a single sample representing only an amount of light, that is, it carries only intensity information. Grayscale images, a kind of black-and-white or gray monochrome, are composed exclusively of shades of gray. The contrast ranges from black at the weakest intensity to white at the strongest.

sRGB standard RGB color space

sRGB is an RGB color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the Internet. It was subsequently standardized by the IEC as IEC 61966-2-1:1999. It is often the "default" color space for images that contain no color space information, especially if the images' pixels are stored in 8-bit integers per color channel.

Adobe RGB color space RGB color space developed by Adobe Systems in 1998

The Adobe RGB (1998) color space is an RGB color space developed by Adobe Systems, Inc. in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as a computer display. The Adobe RGB (1998) color space encompasses roughly 50% of the visible colors specified by the CIELAB color space – improving upon the gamut of the sRGB color space, primarily in cyan-green hues.

A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components. When this model is associated with a precise description of how the components are to be interpreted, the resulting set of colors is called "color space." This section describes ways in which human color vision can be modeled.

ProPhoto RGB color space Photographic color space developed by Kodak

The ProPhoto RGB color space, also known as ROMM RGB, is an output referred RGB color space developed by Kodak. It offers an especially large gamut designed for use with photographic output in mind. The ProPhoto RGB color space encompasses over 90% of possible surface colors in the CIE L*a*b* color space, and 100% of likely occurring real-world surface colors documented by Pointer in 1980, making ProPhoto even larger than the Wide-gamut RGB color space. The ProPhoto RGB primaries were also chosen in order to minimize hue rotations associated with non-linear tone scale operations. One of the downsides to this color space is that approximately 13% of the representable colors are imaginary colors that do not exist and are not visible colors.

LMS color space color space represented by the response of the three types of cones of the human eye

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Photo CD system designed by Kodak for digitizing and saving photos in a CD

Photo CD is a system designed by Kodak for digitizing and saving photos onto a CD. Launched in 1991, the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They were intended to play on CD-i players, Photo CD players, and any computer with a suitable software.

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IT8 is a set of American National Standards Institute (ANSI) standards for color communications and control specifications. Formerly governed by the IT8 Committee, IT8 activities were merged with those of the Committee for Graphics Arts Technologies Standards in 1994.

ColorChecker Color calibration target

The ColorChecker Color Rendition Chart is a color calibration target consisting of a cardboard-framed arrangement of 24 squares of painted samples. The ColorChecker was introduced in a 1976 paper by McCamy, Marcus, and Davidson in the Journal of Applied Photographic Engineering. The chart’s color patches have spectral reflectances intended to mimic those of natural objects such as human skin, foliage, and flowers, to have consistent color appearance under a variety of lighting conditions, especially as detected by typical color photographic film, and to be stable over time.

A color appearance model (CAM) is a mathematical model that seeks to describe the perceptual aspects of human color vision, i.e. viewing conditions under which the appearance of a color does not tally with the corresponding physical measurement of the stimulus source.

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