September 04, 2009

Why your Web content will look darker on Snow Leopard

If you’re a Web designer, expect your CSS colors & your untagged/unmanaged images to look darker on Snow Leopard than on previous versions of the Mac OS. You’ll also see less of a visible color shift when going from Photoshop to Flash or other unmanaged environments (e.g. Internet Explorer).

Why is that? Apple has switched to a default gamma of 2.2, which is what Windows has used for years. Colors that aren’t color-managed are going to look darker on the whole. Your whole display will now be closer to what Windows users see*.

Apple’s marketing materials (and reviews of Snow Leopard) say only that the change is “to better serve the needs of consumers and digital content producers.” Not really knowing what that means, and wondering why Apple would change the Mac to match Windows after 25 years of using gamma 1.8, I sought out more info.

Adobe Principal Scientist Lars Borg provided some perspective. Lars has spent the past 20 years at Adobe defining & driving color management solutions, and lately he’s been focused on digital cinema standards. Here’s what he said:

In the distant past, the computer world was colorless, bleak, stark black and white. No one cared about their display gamma, as gamma is irrelevant for displaying only black and white.

Macintosh, in 1984, introduced us to desktop publishing and to displays with shades of grays. Publishing at that time meant printing presses, and the dot gain of a typical press (then and now) corresponds to a gamma of 1.8. As color management was non-existent at the time (the first color management solutions did not appear until early 1990s, when color displays became more available), Apple’s pick of a 1.8 display gamma enabled the Macintosh displays to match the press.

In early 1990s, the TV industry developed the High-Definition TV capture standard known as ITU Recommendation 709, using a net gamma of around 2. Later, in 1996, IEC put forth a CRT-based display standard (sRGB) for the Web that would match the HDTV capture standard, having a net gamma of around 2.2. sRGB was slowly adopted first in the PC display market, next in the burgeoning digital camera market, and 2.2 became the dominant display gamma.

Is 2.2 the ultimate gamma? No. In 2005, leveraging color science research, the movie studios’ Digital Cinema Initiative selected a gamma of 2.6 as providing the best perceptual quality for 12-bit cinema projection. Today, few can afford a true Digital Cinema display at home, but as always prices are falling. Yes, that’s what I’ll have in my next home theater.

But, recall VHS versus BetaMax. The VHS format finally died with the last video tape. Gamma 2.2 will not be unseated easily. However, calibrated displays and functional color management will make gamma a moot point. Gamma will be for the Luddites.</blockquote

>Interesting stuff. Despite the Flash Player now supporting color management, I’m not holding out hope for Web developers suddenly starting to give a damn about the subject. At least now we’ll be less likely to hear complaints about colors “getting screwed up” when going from Photoshop to the Web.

* For what it’s worth, when I was a Web designer I’d always set my Mac monitor to gamma 2.2, the better to match the darker Windows environments on which my designs were most often viewed.

Posted by John Nack at 10:08 AM on September 04, 2009
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