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Grab your pitchforks, the revolt is on!
By Dave Etchells, The Imaging Resource
(Tuesday, February 13, 2001 - 18:25 EST)

The revolt against the sRGB color space is on! Epson enlists Casio, Konica, Kyocera (Contax/Yashica), Minolta, Olympus, Ricoh, Sony, and Toshiba as partners in a new digicam color standard.

A special "color commentary" from Dave:

In Monday's news, we reported on the "Epson PRINT Matching" digicam/printer color space announcement made by Epson and eight digicam companies about a new color space standard for digicam files. I think this news is important enough that it deserved some special comment, but today is the first chance I've had to sit down and write anything. Also, the initial print samples shown in the press kits which were distributed really missed some of the major potential benefits of the new approach, which we're afraid may lead some reporters to miss the significance of the event.

This strikes me as one of the most significant announcements at the show. This looks like the long-anticipated (by myself, at least) "revolt against sRGB". (Fellow peasants, take up your pitchforks and follow me!)

What it appears to boil down to is (a) An agreement to break free of the limitations of the sRGB color space, and (b) An agreement on a common standard for passing color-space information in the EXIF header of the JPEG files.

There are many implications in the announcement, and specific technical information is very limited at this point, but the impact is going to be a major one for photo enthusiasts. The sRGB color standard was essentially handed down by fiat by Microsoft and HP a while back. It brought order to the graphic-display baseline for the Windows platform, but is really an absolute abomination from a photographic standpoint. Microsoft's interest was to define a least common denominator for display characteristics that could be counted on more or less across the board. The way this was achieved was to more or less restrict the color space to that which could be displayed by the worst monitors in the marketplace. For photo enthusiasts, this was genuinely bad news. The differences between sRGB and color spaces with broader gamuts are for the most part subtle, but can be really electrifying for extreme blue/green hues, and for some reds as well.

Another problem faced by printer and digicam makers is a lack of agreement on a "standard" gamma setting to use in recording and interpreting RGB data. (For instance, Epson has generally used the "graphics" standard gamma of 1.8, while many digicam makers use the sRGB standard value of 2.2. Others split the difference with a gamma value of 2.0. The result can be dark (or light) muddy (or washed out) colors when the digicam files are printed.

Details are still sketchy on the specifics of the new standard, but two key pieces/types of data are stored in the EXIF headers of JPEG files: 1) Gamma setting used to record the original RGB data, 2) Information regarding the color space the RGB data references. Other color-rendering information apparently can also be stored in the EXIF header, such as differential rendering instructions for specific regions of color space (such as the range of pastels corresponding to the always-difficult caucasian skin tones), and "tweaking" parameters for saturation, contrast, and tonal rendering.

The upshot of all this is that digicam manufacturers will gain an enormous amount of control over their camera's color rendering, all the way to the final printed output, regardless of any color space limitations. On the color space front, the artificial limits imposed by the sRGB color space will be relaxed, allowing a much greater range of colors to be reproduced accurately.

To take maximum advantage of the new standard, a camera needs to record it's RGB values based on a different color space than sRGB. The result will be files that appear "flatter" and less saturated on conventional output devices (monitors and non-"PRINT matching" printers), but that are contain a much greater range of color information. Printing such files on a PRINT matching output device will "unlock" the expanded color space.

It's just this fact that explains the relatively modest results seen in the print samples displayed by Epson in the press kits distributed at the announcement celebration: All these were based on files from current cameras, all of which record data in the sRGB color space(!) Thus, none of the samples really illustrated the dramatic improvements possible through the use of alternative color spaces. In a separate briefing though, we saw several samples captured using other, broader-gamut color spaces, and the results were truly stunnning: Electric blues and greens in tropical seas were as bright and vibrant as they appear in nature, and brightly-colored fabrics that were rendered as duller hues by the conventional process practically leapt off the page.

As with any new technology, ultimate success will depend on implementation, and on how much of the industry can be convinced to adopt it. Time will tell how successful Epson and its partners are on the first score, and the whos-who listing of initial partners displayed at the announcement bode well for the latter. Stay tuned!

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