[Openicc] "working space" nitpick

[Chris Murphy]

This is my personal opinion only, although I know a lot of people who  
agree with me, this seems to be minor point among the color geeks. I  
also don't claim to create/define color management terminology.  
Nevertheless, the present day usage of working space and working  
spaces is really confusing to regular users who are not fully  
familiar with the concept, because of the fact that it has two meanings.

"Working Spaces" is an Adobe term. For quite a while it existed no  
where else. Working Spaces is a set of pop-up menu settings. One for  
RGB, CMYK, Gray, and Spot respectively. The Working Spaces settings  
define default profiles. Depending on the Color Management Policies  
(also settings in Adobe applications), the Working Spaces may always  
be used (even in favor of embedded profiles) or only be used for  
untagged images/documents. But it's fair to characterize them as  
default profiles. Examples:

1. If you open any untagged file, the profile that is assumed as  
source is the RGB Working Space or CMYK Working Space.
2. If you use Image>Mode to convert to RGB, Gray or CMYK, the profile  
used as the destination profile are Working Spaces. Whatever they  
happen to be defined as at the moment of conversion.

The other use of the term "working space" or "working spaces", in the  
vernacular, means "a well behaved RGB space suitable for editing  
images in; it's matrix based with the same TRC for each channel (TRC  
can be gamma defined, or with that of a table)." I call these editing  
spaces, or intermediate spaces. They exist because they're well  
suited for editing images in, unlike scanner RGB, camera RGB, or even  
display RGB. Some people call them "work space" which I prefer over  
"working space" even though they're nearly the same word.

The vast majority of profiles that are set as Working Spaces are  
*not* well behaved spaces. You can set a scanner profile as an RGB  
Working Space. If you do so, is scanner RGB a Working Space? Yes it  
is, because it's just a setting. But it makes it confusing if what  
you're really asking is if scanner RGB is a well behaved "editing  
space" or "intermediate space" and the answer to that is no, it isn't.

In a program like InDesign it becomes even more important to make the  
distinction because it also has Document RGB and Document CMYK  
profiles. Anything untagged or native inherits those profiles as  
assumed source. (Document RGB and Document CMYK are also the default  
destination profiles - depending on whether your output device is RGB  
or CMYK.) If Document RGB or Document CMYK are not explicitly set,  
they defer to the Working Spaces.

Anyway, that's my nitpick.



Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)