问题
- Is this (a) an own color space like AdobeRGB and sRGB or is this (b) a name for the RGB color space that the device uses?
(in case it is (b), what color space should be used to render a pdf? is sRGB the default to use? should a pdf viewer application be able to change this 'device' color space?)
回答1:
DeviceRGB simply means that its a 3 component space with Red Green and Blue colourants, it is not calibrated. sRGB is a calibrated space (I believe 'standard' RGB, which is where the 's' comes from), and was created to address the problem that two 'RGB' devices would not necessarily display a given RGB triplet precisely the same. (I'm aware you undoubtedly know this, its for the benefit of later readers)
If you are trying to do colour management (as I assume from your earlier question) then you cannot colour manage a simple DeviceRGB space, all you can do is use the component values as given. sRGB on the other hand is a characterised space, so you can convert that into XYZ and then (as you know) you can go from that to the output space.
Basically you can't colour manage the simple Devioce* spaces, which is why Adobe adopted CIE and ICC spaces in level 2 PostScript and in PDF.
So: No, DeviceRGB is not a characterised space such as AdobeRGB or sRGB, nor in fact is it a name for the RGB space used by the device. When rendering DeviceRGB to an RGB device you should use the R, G and B components as given, you have no clue as to what precise colour was intended by the author, in effect they declared that they didn't care that much. When converting to other spaces you should use the arithmetic given in the PDF specification to do so.
来源：https://stackoverflow.com/questions/36916893/pdf-what-is-devicergb