HP, Corel, and Pantone to Support sRGB

On December 22, 1997, Hewlett-Packard, Corel, and Pantone announced support for Standard RGB color (sRGB) in hardware and software products from the companies. All future printers and scanners from HP will use the sRGB color space. CorelDRAW 8 will use sRGB as its default color space, and will specify Pantone colors using sRGB. Pantone's ColorWeb Pro and future digital products from Pantone will use sRGB as their default color space. In addition sRGB is the default color space for the World Wide Web Consortium and High Definition Television. Intel's digital camera developer's kit accommodates sRGB. And the Japan Electronic Industry Development Association has endorsed sRGB as the standard space for its EXIF file format.

Why does the world need an sRGB space if the ICC is going to manage all of our colors? In a paper titled A Standard Default Color Space for the Internet - sRGB, (November 6, 1996) authors Michael Stokes (Hewlett-Packard), Matthew Anderson (Microsoft), Srinivasan Chandrasekar (Microsoft), and Ricardo Motta (Hewlett-Packard) said, "The ICC profile format does not provide a complete solution for all situations." The authors describe some of the circumstances under which an attached profile such as the ICC profile isn't appropriate:

• There is a broad range of users that do not require the level of flexibility and control that attached profiles offer.

• Most existing file formats do not, and may never, support color profile embedding.

• There is a broad range of uses that actually discourage people from appending any extra data to their files.

Said HP's Michael Stokes, "We view sRGB and ICC as complementary. Even with ICC, with devices in new file formats, you need a baseline for what the RGB behavior is, if only to have a default condition to work from. The problem is that not all devices have profiles, and not all application software and file formats will 'rev' to accommodate profiles." Stokes said that the sRGB team's review of product performance (especially monitor performance) showed that, "everybody is self-consistent, but not consistent with each other."

Readers can find A Standard Default Color Space for the Internet - sRGB at http://www.w3.org/Graphics/Color/sRGB.html. The white paper has evolved, and is now the submission document for review by international standards bodies. Since the November 1996 paper was written, the standard has been tested by Eastman Kodak, Fuji, Sony, and HP. The field work has produced some changes to the numbers. Readers who need the latest specification detail can download the Project Team 61966 Technical Committee 100 draft spec that was submitted on January 9, 1998 to the International Electrotechnical Commission. The address is http://w3.hike.te.chiba-u.ac.jp/IEC/100/PT1966/parts/part2/1966_16.pdf. (Note: case counts.) In the January 9, 1998 document, section C.2 of Annex C Usage Guidelines spells out the motivation for having an alternative to ICC color management.

One benefit of sRGB will be that the overhead of carrying profile information along with the image will be eliminated. In addition, the overhead of performing transformations will be eliminated. SRGB is a colorimetric RGB specification based on the average performance of PC display. The authors of the paper indicated that average PC monitor performance is a reasonable target because most monitors are similar in phosphor chromaticities (primaries) and transfer function. In addition, RGB spaces are native to displays, scanners and digital cameras, which are the devices with the highest performance constraints. Further, according to the report, RGB spaces can be made device independent in a straightforward way, and can also describe color gamuts that are large enough for all but a small number of applications.

If there is a demand for standardized color and color management, it is from the segments whose business is to reproduce color--the commercial printing industry, textile industry, hard-goods manufacturing, and so on. In addition to those who "manufacture" color, color management tools are needed by market segments such as imaging service bureaus and advertising agencies that act as intermediaries or creators.

The commercial printing environment, in particular, is very much a CMYK world. (The commercial printing environment is also a world whose principal color management tool today remains the analog contract proof.) As the commercial printing industry embraces digital techniques, color management in general and ICC profiles in particular will probably see higher degrees of use. With ICC, the print world has a path for managing color. But CMYK is not a natural state for RGB devices such as monitors, scanners, and digital cameras. Transforming from one form or space to another is the crank that causes ICC to work. And so, as a document travels thorough an ICC-managed work flow, the document is transformed to deliver RGB to a monitor the same way the document would be transformed to deliver CMYK to a digital proofer or connected color copier. For ICC-style color management to work, one needs to have an infrastructure of device profiles in place. For ICC-style color management to work, one must know about the performance of all of the components in the work flow. It is reasonable to assume that, at some point, such an infrastructure would be in place in the commercial printing work flow. And the infrastructure doesn't need to be very broad. One only needs profiles for the devices in the work flow for the job at hand.

But now we have the Web. The same team members (commercial printing customers, service bureaus, and graphic artists) are interested in publishing color material on the World Wide Web, where little is known about the devices that will display or print their "publications." "Since a good chunk of work is going to the Web," explained Stokes, "we need a good RGB target." SRGB is needed because it is unlikely that a web-wide set of ICC profiles of monitors, scanners, cameras, and printers will ever be in place. In addition, because web surfers suffer with large files and narrow bandwidth, attaching profile information and processing transformations adds to the download time.

The sRGB proposal, in essence, avoids tagging and profiles by defining a color space and including the definition in the operating system. The "average-PC-monitor" color space has the advantage of being widely understood, it crosses both the computer graphics industry and the consumer electronics industry, it is accommodated by a current reservoir of computer-based documents that exist already in RGB terms, and the performance of the principal "publishing" method, the computer monitor, is reasonably well-behaved.

Color Business Report is an information service of Blackstone Research Associates. Information and analysis presented in this publication are based on the best information available, but cannot be guaranteed for completeness or accuracy. Copyright © 2005 by Blackstone Research Associates. Reproduction without permission prohibited.

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