Re: Lab is always "just right"
Re: Lab is always "just right"
- Subject: Re: Lab is always "just right"
- From: "Vanderlinden, Thomas M." <email@hidden>
- Date: Wed, 12 Sep 2001 10:34:20 -0400
good morning - - - - -
(Even with yesterday's horror's,
it is still a wonderful privilege to be
in the United States.
It is still a good morning.)
I am attempting to digest Steve Upton's two messages
on this thread, and appreciate his response.
I am concerned that some following this thread
may believe that this issue revolves mainly
around esoteric definitions of various color spaces
and is not relevant to production work,
and only of intellectual interest.
(Actually, maybe I should be hoping that is true,
so I can dismiss my worries.)
My primary concern is that it appears that a relatively small color space
(like a GretagMacbeth Eye-One profile of a reflective flatbed scanner
or a four color ink jet profile)
does not fit into the Lab space, and this therefor seems to exclude Lab
from consideration as a useful archive color space,
even in the relatively small area of reflective color scanning.
I guess I am not sure how to use Steve's answer of "no" to the question:
Am I capturing reds that are not surviving
the conversion to Lab?
Does this mean the reflective color scanner is picking up
and then a profiling process is measuring and creating a profile
which includes colors we that we can not see?
I can't imagine a theoretical reason why this could not be true,
but it's doesn't seem very desirable.
Or
does it mean that Lab / PCS will contain all that
the reflective scanner can pick up,
3-D gamut views to the contrary not withstanding?
I am sending some snap shots of 3-D representations
of various spaces overlaid on the Lab space
to Steve Upton of CHROMiX, who reported that he was
not seeing what I described.
Perhaps I am using the tool incorrectly!? (I hope)
The comment from Steve that the PCS *is* Lab D50
perhaps raises broader questions in this context.
I do note that the 3-D viewer seems not to visually demonstrate
the uncontainedness of the Adobe RGB space by the Lab space
of which CDTobie said:
>
Lets take AdobeRGB's pure green: 0, 255, 0. This color is outside Lab's
>
255
>
value limitation, and will clip to the same value as 0, 252, 0 when
>
converted
>
to LAB. Such values outside the ICC Lab space (even though they are inside
>
>
the CIE Lab space which does not share the numerical limitation) are bound
>
to
>
be clipped by ICC color engines.
>
Perhaps the differences in his example are too tiny to graph properly.
- -- - - Tom Vanderlinden
email@hidden
Bridgeport National Bindery
a.w. Thanks to all for their expressions of sympathy
towards those affected by the death & destruction
of yesterday. Who said "All that is necessary for evil to triumph
is for good people to do nothing."?