color management In digital imaging systems, color management (or colour management) is the controlled conversion between the color representations of various devices, such as image scanners, digital cameras, monitors, TV screens, film printers, computer printer ...

, an ICC profile is a set of data that characterizes a color input or output device, or a

color space A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital represent ...

, according to standards promulgated by the

International Color Consortium The International Color Consortium (ICC) was formed in 1993 by eight vendors in order to create an open, vendor-neutral color management system which would function transparently across all operating systems and software packages. Overview The ...

(ICC). Profiles describe the color attributes of a particular device or viewing requirement by defining a mapping between the device source or target

and a ''profile connection space'' (PCS). This PCS is either

CIELAB The CIELAB color space, also referred to as ''L*a*b*'' , is a color space defined by the International Commission on Illumination (abbreviated CIE) in 1976. (Referring to CIELAB as "Lab" without asterisks should be avoided to prevent confusion ...

(L*a*b*) or

CIEXYZ The CIE 1931 color spaces are 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 defin ...

. Mappings may be specified using tables, to which

interpolation In the mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing (finding) new data points based on the range of a discrete set of known data points. In engineering and science, one often has a n ...

is applied, or through a series of parameters for transformations. Every device that captures or displays color can be profiled. Some manufacturers provide profiles for their products, and there are several products that allow an end-user to generate their own color profiles, typically through the use of a

tristimulus colorimeter A tristimulus colorimeter, colloquially shortened to ''colorimeter'', is used in digital imaging to profile and calibrate output devices. It takes a limited number of wideband spectral energy readings along the visible spectrum by using filtered ...

or a spectrophotometer (sometimes called a spectrocolorimeter). The ICC defines the format precisely but does not define algorithms or processing details. This means there is room for variation between different applications and systems that work with ICC profiles. Two main generations are used: the legacy ICCv2 and the December 2001 ICCv4. The current version of the format specification (ICC.1) is 4.4. ICC has also published a preliminary specification for iccMAX (ICC.2) or ICCv5, a next-generation color management architecture with significantly expanded functionality and a choice of colorimetric, spectral or material connection space.

Details

To see how this works in practice, suppose we have a particular

RGB The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three addi ...

and

CMYK The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation ''CMYK'' refers ...

, and want to convert from this RGB to that CMYK. The first step is to obtain the two ICC profiles concerned. To perform the conversion, each RGB triplet is first converted to the Profile connection space (PCS) using the RGB profile. If necessary the PCS is converted between CIELAB and CIEXYZ, a well defined transformation. Then the PCS is converted to the four values of C,M,Y,K required using the second profile. So a profile is essentially a mapping from a color space to the PCS, and from the PCS to the color space. The profile might do this using tables of color values to be interpolated (separate tables will be needed for the conversion in each direction), or using a series of mathematical formulae. A profile might define several mappings, according to rendering intent. These mappings allow a choice between closest possible color matching, and remapping the entire color range to allow for different

gamut 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 circ ...

s. The reference illuminant of the Profile connection space (PCS) is a 16-bit fractional approximation of D50;Specification ICC.1:2004-10 (Profile version 4.2.0.0)
Image technology colour management — Architecture, profile format, and data structure; its

white point A white point (often referred to as reference white or target white in technical documents) is a set of tristimulus values or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction. Depending on ...

is XYZ=(0.9642, 1.000, 0.8249). Different source/destination white points are

adapted In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

using the Bradford transformation. Another kind of profile is the device link profile. Instead of mapping between a device color space and a PCS, it maps between two specific device spaces. While this is less flexible, it allows for a more accurate or purposeful conversion of color between devices. For example, a conversion between two CMYK devices could ensure that colors using only black ink convert to target colors using only black ink.

References in standards

The ICC profile specification, currently being progressed as International Standard ISO 15076-1:2005,ISO 15076-1:2005
Image technology color management–Architecture, profile format and data structure–Part 1: Based on ICC.1:2004-10
/ref> is widely referred to in other standards. The following International and ''de facto'' standards are known to make reference to ICC profiles.

International Standards

* ISO/IEC 10918-1: Coding of still pictures –

JPEG JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and imag ...

* ISO 12234-2: Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format (ISO TC42) * ISO 12639:2004 Graphic technology – Prepress digital data exchange – Tagged Image File Format for Image Technology (

TIFF Tag Image File Format, abbreviated TIFF or TIF, is an image file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers. TIFF is widely supported by scanning, faxing, word processin ...

/IT) (ISO TC130) * ISO/DIS 12647-1: Graphic Technology – Process control for the production of halftone color separations, proof and production prints – part 1: Parameters and measurement methods (Revision under way in ISO TC130) * ISO/DIS 12647-2: Graphic Technology – Process control for the production of halftone color separations, proof and production prints – part 2: Offset processes (Revision under way in ISO TC130) * ISO/CD 12647-3: Graphic technology – Process control for the production of half-tone color separations, proofs and production prints – Part 3: Coldset offset lithography on newsprint * ISO/CD 12647-4: Graphic technology – Process control for the production of half-tone color separations, proof and production prints – Part 4: Publication gravure printing * ISO/CD 12647-6: Graphic technology – Process control for the production of half-tone color separations, proof and production prints – Part 6: Flexographic printing * ISO/IEC 15948:

Portable Network Graphics Portable Network Graphics (PNG, officially pronounced , colloquially pronounced ) is a raster-graphics file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange F ...

file format (jointly defined with W3C – see www.libpng.org/pub/png/spec/iso) * ISO/IEC15444: Coding of still pictures –

JPEG2000 JPEG 2000 (JP2) is an image compression standard and coding system. It was developed from 1997 to 2000 by a Joint Photographic Experts Group committee chaired by Touradj Ebrahimi (later the JPEG president), with the intention of superseding the ...

(ISO JTC 1/SC 2) * ISO 15930-1:2001 Graphic technology – Prepress digital data exchange – Use of PDF. Part 1: Complete exchange using CMYK data (

PDF Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. ...

/X-1 and PDF/X-1a) (ISO TC130) * ISO 15930-3:2002 Graphic technology – Prepress digital data exchange – Use of PDF. Part 3: Complete exchange suitable for color managed workflows (PDF/X-3) (ISO TC130) * ISO 15930-4:2003 Graphic technology – Prepress digital data exchange using PDF – Part 4: Complete exchange of CMYK and spot color printing data using PDF 1.4 (PDF/X-1a) * ISO 15930-5:2003 Graphic technology – Prepress digital data exchange using PDF – Part 5: Partial exchange of printing data using PDF 1.4 (PDF/X-2) * ISO 15930-6:2003 Graphic technology – Prepress digital data exchange using PDF – Part 6: Complete exchange of printing data suitable for color-managed workflows using PDF 1.4 (PDF/X-3) * ISO 22028-1:2004 Photography and Graphic Technology – Extended color encodings for digital image storage, manipulation and interchange – Part 1: Architecture and requirements (ISO TC42) * ISO 12052 / NEMA PS3

Digital Imaging and Communications in Medicine Digital Imaging and Communications in Medicine (DICOM) is the standard for the communication and management of medical imaging information and related data. DICOM is most commonly used for storing and transmitting medical images enabling the inte ...

( DICOM) * ISO 32000-2

Portable Document Format (international standard; originally authored by Adobe Systems, Inc.)

De facto standards

PICT The Picts were a group of peoples who lived in what is now northern and eastern Scotland (north of the Firth of Forth) during Late Antiquity and the Early Middle Ages. Where they lived and what their culture was like can be inferred from ear ...

standard specifications (file format published by Apple Computer Inc.) *

PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Doug Br ...

Language (EPS file format published by Adobe Systems Inc.) * JDF v1.1 Revision A (Job Definition forma
published
by the CIP4 consortium available) * SVG (Scalable Vector Graphics) version 1.1 (file format defined by W3C available from https://www.w3.org/TR/SVG/) * SWOP (Specifications for Web Offset Publications), used for

print jobs, primarily in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

References

External links