&nb= sp;

Display Color Management Standard<= o:p>

VESA=

Video Electronics Stan= dards Association

860 Hillview Court, Suite 150 &nb= sp; = &nb= sp; = &nb= sp; Phon= e: 408-957-9270

M= ilpitas, CA 95035 = ; &n= bsp; = ; &n= bsp; = ; &n= bsp; = ; Fax: 408-957-9277

VESA DISPLAY COLOR MANAGEMENT (DCM) STANDARD

Version = 1<= o:p>

January 6, 2003<= /span>

Purpose

This document describes the overall requirements, data collection, data conversion and data storage format for monitor-specific data needed to perform display color management= as a part of a color managed computer system.

Summary

This document is inten= ded to provide interested parties with standardized enabling information in the area of Display Color Management.

Preface

Scope

This specificat= ion covers the following:

1)&n= bsp; The collection of data that is related to display c= olor management

2)&n= bsp; The conversion of the data to a format suitable for storage in monitor EDID

3) The format for storage of the converted= data into a single EDID descriptor block.

4) Color Management Descriptor (CMD) described is Version 3. Refer to Table in Secti= on 4.

Intellectual Property

While every pre= caution has been taken in the preparation of this standard, the Video Electronics Standards Association and its contributors assume no responsibility for err= ors or omissions, and make no warranties, expressed or implied, of functionalit= y or suitability for any purpose.

Trademarks

All trademarks = used within this document are the property of their respective owners. VESA, DDC= and EDID are trademarks of the Video Electronics Standard Association.

I²C = is a trademark owned by Philips.

Patents

VESA proposals = and standards are adopted by the Video Electronics Standards Association without regard a= s to whether their adoption may involve any patents or articles, materials, or processes. Such adoption does not assume any liability to any patent owner,= nor does it assume any obligation whatsoever to parties adopting the proposals = or standards documents.

Support for this Standard

Clarifications and application notes to support this standard may be written. To obtain the latest standard and any support documentation, contact VESA.

· Fax: &n= bsp; 408-957 9277, direct this note to Technical Support at VESA

· E-mail: = ; support@vesa.org

· Mail: &= nbsp; Technical Support

&nbs= p; &= nbsp; Video Electronics Standards Association

&= nbsp; 860 Hillview Court, Suite 150

&= nbsp; Milpitas, CA 95035

Revision History

Version 1—January 6, 2003

Initial release of the standard

Acknowledgments

T= his document would not have been possible without the efforts of the VESA Displ= ay Committee and the DCM Workgroup. In particular, the following individuals a= nd their companies contributed significant time and knowledge to this document= .

Henry D'Souza<= /span>, DCM Workgroup Leader	Compaq Compu= ter Corp.
Karling Chiu	Compaq Compu= ter Corp.
= Mike Fung	DigitalQuake
= Joe Goodart	Dell Computer Corp.
Jim Webb	Genesis Micr= ochip Inc.
= Graham Loveridge	Genesis Micr= ochip Inc.
= Bob Myers	Hewlett-Pack= ard Company
= Susan Luerich	IBM Corp.
= Michael Stokes	Microsoft
= Jack Hosek	NEC-Mitsubis= hi Electronics Display
= Ian Miller	Samsung=
Don Chambers	Total Technologies
Alain d’Hautecourt	ViewSonic
= Sam Shearer	WayTech Development Inc.

Referenced Documents:

· VESA Enhanced Extended Display Identification Data Standard (E-EDID), Release A, Rev. 1, Feb 9, 2000

· VESA Display Specifications and Test Procedu= res (DSTP), Version 1.0 Revision 1.0, Oct 3, 1994

· VESA Flat Panel Display Measurements Standard (FPDM2), Version 2.0, May 2001

· ICC Specification ICC.1:2001-12 File Format = for Color Profiles (Ver. 4.0) or newer – w= ww.color.org

· VESA Display Information Extension Block Standard (DI-EXT), Release A, August 21, 2001

· Enhanced EDID Implementation Guide (companion document to E-EDID standard), Ver. 1, June 4, 2= 001

Table of Contents

Color Management Data Proposal.= ...........................................................................= 1

Acknowledgments..........................................= ..................................................................... 3

1. &= nbsp; Overview.= ...........................................................................= .............................................. 5

2. Data Collection.....................................................................= ..................................... 6

2.1 &= nbsp; Chromaticity..........................................= ........................................................................ 6

2.2 &= nbsp; Tonal Response..........................................= ..................................................................... 6

3. &= nbsp; Data Conversion.....................................................................= ..................................... 7

4. &= nbsp; Data Storage Format.................................................................= .............................. 9

5. Numerical Example.........= ...........................................................................= .............. 10

Appendix A: Polynomial Representation of Tonal Response..................... 13

6. &= nbsp; GLOSSARY.= ...........................................................................= ............................................ 18

1.&n= bsp; Overview

With r= egard to computer displays, it is recognized that the colors produced by a display a= re a result of various proportional mixes of the primary display colors. It is a= lso recognized that each primary color of a specific display could be different from one display to the next, and that the brightness response of each color channel may be different from one display to the next as well as from one c= olor channel to the next on the same display.&n= bsp; From a color management perspective then, it is difficult to render = an exact desired shade of color by mixing uncontrolled amounts of unknown prim= ary colors. To facilitate optimum= color management it is necessary to characterize the brightness response of each display color channel as well as the exact shade of each primary color of e= ach specific display device. This specification is fundamentally intended to address a standard by which these display specific characteristics that are pertinent to color matching may be consistently measured and efficiently stored within the basic EDID™ structure as defined in the VESA E-EDID Standard Release A, Revision 1, February 9, 2000.

From a= display manufacturing point of view, involvement in color management boils down to executing the simple procedure outlined in this standard. However, this is one of the most critical and enabling steps for seamless color manag= ement = (not involving the use of sensors or subjective user feedback in the usage scenario). When a color manag= ement enabled monitor is finally connected to a host computer, the color manageme= nt data contained in the monitor EDID can be easily accessed by software resid= ent on the computer. This softwar= e can then utilize the color management data to create a customized ICC profile f= or the specific display. The mon= itor- specific ICC profile contains display channel colorant tags as well as disp= lay channel tonal response curve tables. For details on how these tags are created, please refer to the ICC specification document.

It sho= uld be noted that the color management data measured at the factory is generally measured in the default factory-shipping color temperature setting. However, this is not necessarily a= hard and fast rule so much as a guideline. A possible instance where this gui= deline may certainly be deviated from would be when a display has a pre-set, user selectable, color temperature setting intended for image viewing as opposed= to computer data viewing. In this circumstance, it may be considered to be more appropriate to make the color management characterizing data measurements at the preferred color temperat= ure setting. The understanding be= ing that the data would be optimally utilized at this color temperature setting= .

VESA provides support for Color Management related data with EDID2.0, E-EDID and DI-EXT. In base EDID there is= a provision for defining a basic “gamma” value in the simple exponential display response model. In DI-EXT and EDID 2.0 there is a provision for defining either a wh= ite response curve or RGB response curves using a finite number of data points. = This document provides a method for efficiently compressing a significant amount= of color related data into a single 18-byte descriptor in the base 128-byte ED= ID or a possible future EDID extension block.

Individual manufacturers m= ay select the most appropriate color data storage method based upon their spec= ific applications and constraints.