Lab color space

A Lab color space is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed (e.g. CIE XYZ color space) coordinates. The terminology originates from the three dimensions of the Hunter 1948 color space, which are L, a, and b. However, Lab is now more often used as an informal abbreviation for the L-a-b representation of the CIE 1976 color space (or CIELAB, described below). The difference between the original Hunter and CIE color coordinates is that the CIE coordinates are based on a cube root transformation of the color data, while the Hunter coordinates are based on a square root transformation. Other examples of color spaces with Lab representations include the CIE 1994 color space and the CIE 2000 color space.

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.

Lab

Lab usually refers to:

Lab or LAB, or variant may also refer to:

Places

People

Music

Transportation

Science and technology

Dan Margulis

Dan Margulis (born 21 December 1951) is an expert on color correction and reproduction of photographs, using Adobe Photoshop or similar software.

His Professional Photoshop series (first edition 1994, currently in its fifth edition, 2006) is widely viewed as an authoritative work in the field of digital color correction of photographs. His Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace (first edition 2005, second edition 2015) established the usage of L*a*b* as a standard part of the repertory of high-end retouchers. His magazine column, Makeready, which ran from 1993 to 2006, introduced many concepts in color handling that have since become accepted practice in the industry. The column appeared in several publications worldwide. In its later years, it was carried simultaneously by Electronic Publishing and Photoshop User magazines in the United States.

Body of work

The work of Margulis is associated with the concept that digital color correction should seek to correspond to what a human observer would see if placed in the position of the camera. He popularized, but did not originate, a method he described as "color by the numbers", which requires the retoucher to verify that certain values in the digital file agree with known standards.