File:CIE1931xy_ColorChecker_SMIL.svg, 300px, Nominal chromaticities of ColorChecker patches in the CIE 1931 xy chromaticity diagram (in th
SVG version
hover over a color swatch to highlight it; click it to select and deselect it) defaul

The ColorChecker color chart, Color Rendition Chart (often referred to by its original name, the Macbeth ColorChecker or simply Macbeth chart) is a

color calibration The aim of color calibration is to measure and/or adjust the color response of a device (input or output) to a known state. In International Color Consortium (ICC) terms, this is the basis for an additional color characterization of the device ...

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''.C. S. McCamy, H. Marcus, and J. G. Davidson (1976)
"A Color-Rendition Chart"
''Journal of Applied Photographic Engineering'' 2(3). 95–99. 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 Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of th ...

, and to be stable over time.

Design

The ColorChecker Classic chart is a rectangular card measuring about , or in its original incarnation about , an aspect ratio approximately the same as that of

35 mm film 35 mm may refer to: * 135 film, a type of still photography format commonly referred to as 35 mm film * 35 mm movie film 35 mm film is a film gauge used in filmmaking, and the film standard. In motion pictures that record on f ...

.Charles Poynton (2008)
"ColorChecker (‘Macbeth’) Chart"
poynton.com It includes 24 patches in a 4 × 6 grid, each slightly under square, made of

matte paint Sheen is a measure of the reflected light ( glossiness) from a paint finish. ''Glossy'' and ''flat'' (or ''matte'') are typical extreme levels of glossiness of a finish. Glossy paints are shiny and reflect most light in the specular (mirror-lik ...

applied to smooth paper, and surrounded by a black border. Six of the patches form a uniform gray

lightness Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a stan ...

scale, and another six are

primary colors A set of primary colors or primary colours (see spelling differences) consists of colorants or colored lights that can be mixed in varying amounts to produce a gamut of colors. This is the essential method used to create the perception of a bro ...

typical of chemical photographic processes –

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...

green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

blue Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when obs ...

cyan Cyan () is the color between green and blue on the visible spectrum of light. It is evoked by light with a predominant wavelength between 490 and 520 nm, between the wavelengths of green and blue. In the subtractive color system, or CMYK color ...

magenta Magenta () is a color that is variously defined as pinkish- purplish-red, reddish-purplish-pink or mauvish-crimson. On color wheels of the RGB (additive) and CMY (subtractive) color models, it is located exactly midway between red and blue. I ...

, and

yellow Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the R ...

. The remaining colors include approximations of medium light and medium dark

human skin The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most ...

, blue

sky The sky is an unobstructed view upward from the surface of the Earth. It includes the atmosphere and outer space. It may also be considered a place between the ground and outer space, thus distinct from outer space. In the field of astronomy, ...

, the front of a typical

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

, and a blue

chicory Common chicory ('' Cichorium intybus'') is a somewhat woody, perennial herbaceous plant of the family Asteraceae, usually with bright blue flowers, rarely white or pink. Native to the Old World, it has been introduced to North America and Austra ...

flower. The rest were chosen arbitrarily to represent a gamut "of general interest and utility for test purposes", though the

orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower *Orange (colour), from the color of an orange, occurs between red and yellow in the visible spectrum * ...

and yellow patches are similarly colored to typical

oranges An orange is a fruit of various citrus species in the family Rutaceae (see list of plants known as orange); it primarily refers to ''Citrus'' × ''sinensis'', which is also called sweet orange, to distinguish it from the related ''Citrus × ...

and

lemon The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The tree's ellipsoidal yellow fruit is used for culin ...

s. There is also a ColorCheckerPassport, a smaller version of the ColorChecker Classic with the same 24 chips but in a tri-fold version with some additional patches on two of the pages. Its dimensions are 125mm (H) × 90mm (W) × 9mm (T). The pigments for ColorCheckerPassport were modified in November 2014, so the current available cards do not have exactly the same carnation, and hence RGB numbers, as before, and particularly are not the ones provided on next section.

Colors

The colors of the chart were described by McCamy ''et al.'' with

colorimetric Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...

measurements using the CIE 1931 2° standard observer and

Illuminant A standard illuminant is a theoretical source of visible light with a spectral power distribution that is published. Standard illuminants provide a basis for comparing images or colors recorded under different lighting. CIE illuminants The Inter ...

C, and also in terms of the

Munsell color system In colorimetry, the Munsell color system is a color space that specifies colors based on three properties of color: hue (basic color), chroma (color intensity), and value ( lightness). It was created by Professor Albert H. Munsell in the first ...

. Using measured reflectance spectra, it is possible to derive CIELAB coordinates for Illuminants ''D''₆₅ and ''D''₅₀ and coordinates in

sRGB sRGB is a standard RGB (red, green, blue) color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the World Wide Web. It was subsequently standardized by the International Electrotechnical Commission ( ...

(''D''₆₅).

Use

Color targets such as the ColorChecker can be captured by cameras and other color input devices, and the resulting images’ output can be compared to the original chart, or to reference measurements, to test the degree to which image acquisition reproduction systems and processes approximate the human visual systems. It can also be used to color correct one photo with the chart in it (that may have a different color cast, for example due to a lighting coloration difference) to another "reference" photo with the chart in it. Because of its wide availability and use, its careful design, and its consistency, and because comprehensive

spectrophotometric Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spec ...

measurements are available, the ColorChecker has also been used in academic research into topics such as

spectral imaging Spectral imaging is imaging that uses multiple bands across the electromagnetic spectrum. While an ordinary camera captures light across three wavelength bands in the visible spectrum, red, green, and blue (RGB), spectral imaging encompasses ...

.For example, Roy S. Berns and Lawrence A. Taplin (2006)
"Practical Spectral Imaging Using a Color-Filter Array Digital Camera"

ColorChecker Digital SG

X-Rite also sells a 140-patch chart called the ColorChecker Digital SG, and is intended for automated use with computer software to characterize digital cameras and scanners.

References

External links

"ColorChecker Classic"
official product page at the X-Rite website for the full size, 24 patch version of the chart.
ColorChecker Passport
official product page for the small, 24 patch version of the chart.
"ColorChecker Digital SG"
official product page for the full size, 140 patch version of the chart * Danny Pascale (2009)

Babelcolor.com. This extensive page includes a history of the chart, average spectrophotometric measurements from 20 ColorCheckers (the precise tools used for these measurements is unclear), calculated RGB values in a variety of

RGB color spaces An RGB color space is any additive color space based on the RGB color model. An RGB color space is defined by chromaticity coordinates of the red, green, and blue additive primaries, the white point which is usually a standard illuminant, and t ...

, a list of places to buy charts, and advice for using the data in practical camera calibration and image applications. ** Danny Pascale (2006
"RGB coordinates of the Macbeth ColorChecker"
Includes comparisons in CIELAB and RGB values based on spectrophotometric measurements vs. provided by Gretag–Macbeth * Bruce Lindbloom (2007)

brucelindbloom.com. Lindbloom measured the spectral reflectances his own copy of the ColorChecker, and created a Java applet to calculate colorimetric coordinates under various

standard illuminant A standard illuminant is a theoretical source of visible light with a spectral power distribution that is published. Standard illuminants provide a basis for comparing images or colors recorded under different lighting. CIE illuminants The Inter ...

s and in various RGB color spaces ** Bruce Lindbloom (2008)
"ColorChecker RGB Summaries, Spreadsheets and Lab TIFF File"
brucelindbloom.com. A page showing RGB values for color patches in various RGB color spaces, based on the applet described above, and a set of Excel spreadsheets for comparing these numbers to those in a digital camera or scanner image of the ColorChecker. {{DEFAULTSORT:Colorchecker Photography equipment Color schemes

Design

Colors

Use

ColorChecker Digital SG

See also

References

External links