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>They are millions of colors and pixel depth is increasing. Um, no. Nobody is serving anything more than 8 bpc on a web page, and nobody has a monitor that cou
by mistercow 14y ago
>They are millions of colors and pixel depth is increasing.
Um, no. Nobody is serving anything more than 8 bpc on a web page, and nobody has a monitor that could show it to them if they did.
- csense 14y agoThe real limitation is the number of colors that can be distinguished by the human eye. I've read that medical scanners and other science-y imaging gear can sample intensity with 16-bit resolution. But if you're talking about hardware whose sole purpose is displaying images for humans to view, having more than 8 bits is just a waste of resources.
- majormajor 14y agoThere's plenty of room for increased dynamic range, if not more colors, than what 8 bits per channel gives us. See raw files from digital cameras, HDR, etc.
- Dylan16807 14y agoI might buy 10 bits, but it's pretty easy to distinguish 8-bit brightness levels. Edit: Found a source quoting 450 light levels the eye can distinguish, so adding a bit of buffer for smooth transitions and imperfect gamma you'd need 10 or 12 bits.
- liuliu 14y agoAlso it depends on the color, for blue, 8 bits may be sufficient, but definitely not green.
- Dylan16807 14y agoRods pick up blue just fine, so I don't think you can skimp on any color.
- mistercow 14y agoRed is picked up about half as well as green, and blue is discerned about half as well as red. You can definitely skimp on blue.
- Dylan16807 14y agoI strongly disagree. Blue is less bright to rods, that's it. If you happen to be looking at even gray, then sure the fact that blue seems a quarter as bright means you can chop off two bits. But if you look at pictures that are blue, without a lot of other colors to wash it out, you're going to have the exact same 450 distinct brightness levels over the 100:1 contrast ratio that the eye picks up.
- mistercow 14y agoLot's of cameras can capture more than 8 bpc too, but there's no point in displaying them that way. The reason it's useful is that it reduces loss of quality when manipulating the colors in the images.
- Terretta 14y agoNot just "science-y" imaging gear. I'm scanning slides today with a Nikon Coolscan 5000ED, and it's a full 16 bits per channel of R, G, and B, and 16 bits of infrared (48 bits + 16 bits). The "raw" TIFFs are 182 MB, while the final JPEGs range between 2.2 and 6.9 MB.