On Mar 4, 2005, at 12:22 PM, Godfrey DiGiorgi wrote:
AdobeRGB allows a significantly greater number of colors to be represented without clipping.
Yes, this is correct. The most significant difference is in the green channel. Red and blue don't seem to be much bigger than with sRGB (in fact the difference in the blue channel is very small indeed). As a consequence the cyan channel in sRGB is comparatively weak, and this makes it struggle a bit when driving CMYK printers (ie inkjets).
If you're going to be editing photos, it's much better to store the originals with AdobeRGB colorspace and render them to whatever colorspace requirements are set by the output printer or web display.
As a general rule this is pretty good advice. There are arguments for using even bigger colour spaces but there are tradeoffs involved, and the decision depends a lot on the image capture (ie digital camera or film scanner), and whatever processing may have been applied to the file before archiving.
I'm having a fiddle with the ColorSync Utility which does 3D plots and comparisons of profiles. Theoretically my film scanner can exceed Adobe RGB. EktaSpace is a better match but I'd need ProPhoto RGB to enclose it almost entirely. I still need to run some tests with my Q60 slide to find out exactly what is practical though, as the film itself has its own limitations. I might grab some highly saturated photos to test with as well.
As an aside, I didn't realise I had a "Web Safe Colours" profile on my system. As you might expect, it's just a set of discrete points spread evenly across the 3D sRGB colour space.
I haven't read it yet, but I suspect that Bruce Fraser's "Real World Color Management" would cover all of these kinds of topics in depth.
I've learned a lot from his writings. He has several articles on the web but some of the better ones can be hard to find (sorry I don't have them bookmarked anymore).
Cheers,
- Dave
http://www.digistar.com/~dmann/
