Color chart

An IT8.7 Target by LaserSoft Imaging used for color management of digital cameras or scanners.

A color chart or color reference card is a flat, physical object that has many different color samples present. They can be available as a one page chart, or in the form of swatchbooks or color-matching fans.

Typically there are two different types of color charts:

Color reference charts

Color reference charts are used for color comparisons and measurements such as checking the color reproduction of an imaging system, and calibration and/or profiling of digital input devices such as digital cameras, and scanners and output display systems like printers, monitors and projectors. They are also used by traditional photographers and cinematographers to calibrate cameras that use film and to check the color temperature of the lighting.

Color reference cards can also be used to assess light quality, as in the color rendering index, where reflectance from a set of Munsell samples are evaluated.

The Von Luschan's chromatic scale for classifying skin color.

Shirley cards

Shirley cards are color reference cards that are used to perform skin-color balance in still photography printing. The industry standard for these cards in North American photography labs in the 1940s and 1950s depicted a solitary "Caucasian" female dressed in brightly colored clothes. Very few of these color reference cards showed an adult male as the reference image.[1] Light skin tones therefore served as the recognized skin ideal standard. Stock color film chemistry for still cameras was designed originally with a positive bias toward "Caucasian" skin tones because of its high level of reflectivity.[1]

By the mid-1990s, Japanese companies redesigned their Shirley cards using data from their own color preference tests. The new reference card featured Japanese women with light yellow skin.[1]

In 1995, Kodak designed a multiracial norm reference card. This card showed three women (Caucasian, Asian, African) with different skin colors and brightly contrasted clothing.[1]

ColorChecker charts

Main article: ColorChecker

The ColorChecker—first produced as the “Macbeth ColorChecker” in 1976—a cardboard-framed arrangement of twenty-four squares of painted samples based on Munsell colors. Its previous maker Gretag–Macbeth was acquired in 2006 by X-Rite.

ColorChecker Color Rendition Chart

A ColorChecker chart can be used to manually adjust color parameters (e.g. color temperature) to achieve a desired color rendition. ColorChecker charts are available in different sizes and forms.

IT8 charts

Main article: IT8

Standardized IT8 charts (also called IT8 targets) are made by several companies including Coloraid.de, FujiFilm, Kodak, LaserSoft Imaging.[2] Unlike ColorChecker charts, IT8 charts are supplied with measurement values and can be used to create ICC color profiles by software (e.g. for digital cameras) to create reproducible color management.

This is an IT8 color target made in EGM Laboratories in Barcelona, Spain. It has a very big gamut, slightly bigger than the ProPhoto color space.

Other

Color charts can take custom forms, as for example the "calibration target" used by the Curiosity rover for its Mars Hand Lens Imager (MAHLI).

(Image courtesy of JPL)
Calibration Target on the Mars Curiosity rover (3-D image).

Color selection charts

Because paints and inks depend for their color on pigments and dyes, a reference is needed to match specific combinations of coloring substances in a given matrix against the resulting color. One of the earliest attempts to achieve this goal was the 1692 manuscript Klaer Lightende Spiegel der Verfkonst. It presented a range of watercolor mixtures, but remained relatively unknown, because only one manuscript was produced. Due to the development of the paint and ink industry, the requirement for this kind of chart intensified, and a number of systems are now available, including:

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 Roth, Lorna (March 28, 2009). "Looking at Shirley, the Ultimate Norm: Colour Balance, Image Technologies, and Cognitive Equity". Canadian Journal of Communication (Canadian Journal of Communication/CCSP Press) 34 (1). Retrieved November 4, 2013.
  2. ↑ Ian Lyons. "IT8 Calibration Targets: Does cost really make a difference?". Computer Darkroom.
  3. ↑ William E. Kasdorf (2003). The Columbia Guide to Digital Publishing. Columbia University Press. ISBN 978-0-231-12498-0.