ICC profile
Encyclopedia
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.
Every device that captures or displays color can be profiled. Some manufacturersicc profiles download provide profiles for their products, and there are several productsList of rip's that allow an end user to generate his or her own color profiles, typically through the use of a tristimulus colorimeter
or preferably a spectrophotometer.
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. , the current version of the specification is 4.2,Version 4 ICC Specification but most devices support only version 2.
, 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.
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
s.
The reference illuminant of the Profile connection space (PCS) is a 16-bit fractional approximation of D50; its white point
is XYZ=(0.9642, 1.000, 0.8249). Different source/destination white points are adapted
using the Bradford transform.
Color management
In digital imaging systems, color management is the controlled conversion between the color representations of various devices, such as image scanners, digital cameras, monitors, TV screens, film printers, computer printers, offset presses, and corresponding media.The primary goal of color...
, an ICC profile is a set of data that characterizes a color input or output device, or a color space
Color space
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...
, according to standards promulgated by the International Color Consortium
International Color Consortium
The International Color Consortium was formed in 1993 by eight industry vendors in order to create a universal color management system that would function transparently across all operating systems and software packages....
(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
Color space
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...
and a profile connection space (PCS). This PCS is either CIELAB
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 CIE XYZ color space coordinates....
(L*a*b*) or CIEXYZ
CIE 1931 color space
In the study of color perception, one of the first mathematically defined color spaces is the CIE 1931 XYZ color space, created by the International Commission on Illumination in 1931....
. Mappings may be specified using tables, to which interpolation
Interpolation
In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points....
is applied, or through a series of parameters for transformations.
Every device that captures or displays color can be profiled. Some manufacturersicc profiles download provide profiles for their products, and there are several productsList of rip's that allow an end user to generate his or her own color profiles, typically through the use of a tristimulus colorimeter
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 photodetectors; e.g...
or preferably a spectrophotometer.
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. , the current version of the specification is 4.2,Version 4 ICC Specification but most devices support only version 2.
Details
To see how this works in practice, suppose we have a particular RGB and CMYK color spaceColor space
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...
, 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.
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
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 circumstance, such as within a given color space or by a...
s.
The reference illuminant of the Profile connection space (PCS) is a 16-bit fractional approximation of D50; its white point
White point
A white point is a set of tristimulus values or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction. Depending on the application, different definitions of white are needed to give acceptable results...
is XYZ=(0.9642, 1.000, 0.8249). Different source/destination white points are adapted
Chromatic adaptation
Chromatic adaptation is one aspect of vision that may fool someone into observing a color-based optical illusion, such as the same color illusion.An object may be viewed under various conditions. For example, it may be illuminated by sunlight, the light of a fire, or a harsh electric light...
using the Bradford transform.
International Standards
- ISO/IEC 10918-1: Coding of still pictures - JPEGJPEGIn computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
- ISO 12234-4: Photography - Electronic still-picture imaging – Part 4: Exchangeable image file format (Exif 2.2) (ISO TC42)
- ISO 12639:2004 Graphic technology — Prepress digital data exchange — Taged Image File Format for Image Technology (TIFF/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 12647-3: 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 file format (jointly defined with W3C – see www.libpng.org/pub/png/spec/iso)
- ISO/IEC15444: Coding of still pictures - JPEG2000 (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/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 MedicineDigital Imaging and Communications in MedicineDICOM is a standard for handling, storing, printing, and transmitting information in medical imaging. It includes a file format definition and a network communications protocol. The communication protocol is an application protocol that uses TCP/IP to communicate between systems...
(DICOM)
De-facto standards
- PICTPICTPICT is a graphics file format introduced on the original Apple Macintosh computer as its standard metafile format. It allows the interchange of graphics , and some limited text support, between Mac applications, and was the native graphics format of QuickDraw.The original version, PICT 1, was...
standard specifications (file format published by Apple Computer Inc.) - PostScriptPostScriptPostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
Language (EPS file format published by Adobe Systems Inc.) - PDF Portable Document Format (file format published by Adobe Systems Inc.)
- JDFJDFThe term JDF may refer to:*Jamaica Defence Force*Japan Self-Defense Forces*Job Definition Format*Juvenile Diabetes Research Foundation, formerly known as the Juvenile Diabetes Foundation...
v1.1 Revision A (Job Definition format published by the CIP4 consortium available) - SVG (Scalable Vector Graphics) version 1.1 (file format defined by W3C available from http://www.w3.org/TR/SVG)
- SWOP (Specifications for Web Offset Publications), used for CMYKCMYK color modelThe CMYK color model is a subtractive color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four inks used in some color printing: cyan, magenta, yellow, and key...
print jobs, primarily in the United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
External links
- SpaceMan ICC - ICC management and LUT conversion
- ICC Frequently Asked Questions
- ICC profile specification
- Is your system ICC Version 4 ready? An ICCInternational Color ConsortiumThe International Color Consortium was formed in 1993 by eight industry vendors in order to create a universal color management system that would function transparently across all operating systems and software packages....
test page for browsers - ICC profiles in Adobe Photoshop ### new link
### - ICC profiles in FastPictureViewer
- ICC profiles for CMYK systems
- CoCa - Open source ICC profile creator by Andrew Stawowczyk Long