Color management glossary
This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP.
Alternate CMM | A CMM implemented in customer code which the RIP may optionally use to invoke ICC color transforms and/or CMM custom color spaces. |
Bidirectional profile | An ICC profile that contains both device to PCS and PCS to device conversions. |
Blend space | The device space used in a transparency group for compositing operations. It may be tagged or untagged. |
CAT | Chromatic Adaptation Transform. |
CIE | International Commission on Illumination. Usually, abbreviated CIE for its French name, Commission Internationale de l'Éclairage. |
CIE color space | One of the standard PDF and PostScript color spaces that convert colors to the CIE XYZ color space, e.g. |
CMYK | Cyan, Magenta, Yellow and Black. The ink colors used when process printing. Jobs for four color process printing are separated into CMYK. |
CxF/X-4 | Color data exchange format, part 4. It's an ISO file format for specifying spot color characterisation data that has been adopted as part of the PDF specification. |
BPC | Black Point Compensation. |
CMM | Color Management Module for ICC color management. |
CMM custom color space | A color space implemented in customer code as part of an Alternate CMM, usually written in C. One or more may be used by color configuration operators. |
CMS | Color Management System. This may include a CMM. |
CMYKOG | An XG colorant set comprising Cyan, Magenta, Yellow, Black, Orange, and Green. |
Color pipeline | A series of individual color transforms that collectively convert color from a graphical object's color to the output device. There may be many, only one, or even zero, transforms in any given pipeline. |
Color transform | Typically, a conversion from one device space to another. Commonly, this can be modelled using input/output ICC profiles, but many other transforms are supported. |
CRD | Color Rendering Dictionary. The standard PostScript language method of configuring the rendering applied to device independent colors. |
CSA | Color Space Array. The standard PostScript language and PDF method of configuring a color space in which colors are interpreted. Usually applied to device independent color spaces. |
Destination profile | An ICC profile that will be used for converting color from the PCS to the destination device. It must contain suitable tags for this conversion. |
DeviceLink profile | An ICC profile that converts color between two device spaces. The PCS is not used in these profiles. |
Device space | A color model describing the color of the device. Conventional examples are CMYK, RGB, and Gray. |
ICC | ICC specification, http://www.color.org/icc_specs2.xalter. |
Lab | A CIE standard device independent color space often used as the PCS in ICC profiles. It is designed to be perceptually linear. |
NCD | Named color database, also known as a named color resource. |
Page group | The transparency group that contains the whole page. The result of compositing the page group is a backdrop raster of the whole page. PDF jobs often contain an explicit page group. The RIP creates an implicit page group in all other jobs, including PostScript language jobs, this is called the Virtual Device in the RIP. |
PCM | The |
PCS | The Profile Connection Space of an ICC profile. When a source and destination profile are used in a color transform, colors are converted to the PCS of the source profile before passing them to the destination profile. The PCS is either XYZ or Lab. |
Skin | The code written around the Harlequin RIP core. This includes the SDK code (skinkit) and application code (e.g. skintest). |
Source profile | An ICC profile that is used for converting color from the source to the PCS. It must contain suitable tags for this conversion. |
Tagged device space | A CMYK, RGB, or Gray device space associated with a color space definition, for example, CMYK associated with a CMYK ICC input profile. |
Transparency mode | When the RIP is processing a transparent job. |
Transparency group | A subset of the graphical objects on a page in which compositing is applied consistently. The result of compositing is a backdrop raster expressed in the groups blend space. Transparency groups may be nested to contain child groups. |
Transparency group stack | A set of nested transparency groups resulting from the ability of graphics applications to place both graphical objects and transparency groups in another transparency group. The transparency group stack starts with a graphical object at the top of the stack and the page group is at the bottom. |
Untagged device space | A device space without a defined color space, for example, CMYK without an associated ICC profile. |
Virtual device | An internal transparency page group created by the RIP for the purpose of compositing. The behavior of the virtual device depends on the setting of |
XG | Extended gamut device. A press that is capable of printing colors outside the gamut of conventional CMYK presses by the use of additional colorants. XG presses often use CMYK + Orange, Green, and/or Violet. |
XYZ | A CIE standard device independent color space often used as the PCS in ICC profiles. It is designed to be colorimetrically linear. |