On Jun 25, 2017, at 21:28 , Gerriet M. Denkmann <gerri...@icloud.com> wrote: > >> On 26 Jun 2017, at 08:03, Graham Cox <graham....@bigpond.com >> <mailto:graham....@bigpond.com>> wrote: >> >> Well, it depends on what you want to do with the image. If it’s content that >> gets displayed or printed, then calibrated ensures that it will look the >> same across a range of devices. > > As my pixels are either white or black, this “Calibrated” seems not to be > important. > Also: it bloats my images: > // Device subPngData 337 bytes b&w > // Calibrated subPngData 1434 bytes b&w > So I’ll stick with “Device”.
You should pay more attention to what Graham said. It depends on what you want to do with the image. If you specify a device space, the images may not appear black&white, but light gray and dark gray with a color cast, with different distorted grays on different devices. (Colorspaces are about calibrating white and black as much as they are colors.) It also depends where the pixel values are coming from. If you’re arbitrarily setting the pixel values to 0 or 1.0 (or 0 or 255), that doesn’t mean you’ll get blacks and white with *either* of those color spaces. — If you specify “device”, the Mac will pass those raw values to the display, which will interpret them according to whatever colorspace it’s calibrated for. — If you specify “calibrated”, the Mac will interpret those values in the standard Calibrated color space, then do a color conversion to whatever colorspace the display is calibrated for. Either way, you get something that isn’t likely to be exactly white or black. The difference is that using Calibrated will give the same “wrong” color on all displays, but Device will give different “wrong” colors on different displays. To get actual blacks and whites, you need to set the pixel values to whatever represents proper black and white in whatever colorspace you intend to attach to the image. Getting those pixel values to begin with is the tricky part. Having said all that, I have to admit that the difference between using uncalibrated/misconverted whites and blacks is likely to be minor. Again, it depends on what you’re doing whether that’s acceptable or not. _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
