"Jeffrey" wrote in message
While exactly is the difference between the Adobe RGB and sRGB workspaces. I know tht the Adobe RGB workspace is suppossed to contain more colours
than
the sRGB workspace, but I cannot understand this, if they both seemed to
be
based upon 3 channels of 8 bit colours.
The difference occurs only because of the *way* these three channels of information
are interpreted. A typical RGB image file, as you say, is just three channels with 8-bits
of resolution, and has absolutely zero colour in itself. 🙂 It’s only when this information
is interpreted and displayed that colour results.
In Adobe RGB, the red, green, and blue colourants are different to that in sRGB,
so a given RGB pixel value is mixing together different red green and blue primary
colours. Because the primary colours on which the Adobe RGB colour space is modelled on are "purer" than the primary colours which sRGB is modelled on, the range of colours which can be represented in Adobe RGB is larger than sRGB.
This does not mean that an Adobe RGB image is going to produce a wider colour
range on a standard monitor – the colour range of a standard monitor is limited by
it’s phosphors. (NEC/Mitsubishi are bringing out an expensive monitor which really
*can* display almost all of the Adobe RGB colour gamut, however, and I understand
there are already other very expensive monitors with appreciably wider gamut than standard)
My understanding is that the *most* important hues which Adobe RGB can reproduce
which sRGB cannot is cyans – it is cyans which printers can produce significantly better
than a standard monitor, and so using a working space of Adobe RGB allows these colours
to be represented in the digital image file, *despite* the fact that they can’t be displayed
entirely accurately on almost everybody’s monitors.
Now, when Mike says this:
sRGB is closer to a "generic" monitor, and will have brighter colors than Adobe RGB when viewed on most web browsers, and other programs that do not know about color management.
the reason this occurs (and it occurs only when the program displaying the image does
not know about colour management) is that typically, any given colour will be represented
by pixel values a bit less in Adobe RGB than in the sRGB space, simply because the
RGB primaries need less driving strength in Adobe RGB, because they are purer primaries.
Greg.
Jeffrey
