Re: Lab is always "just right" P2
Re: Lab is always "just right" P2
- Subject: Re: Lab is always "just right" P2
- From: Steve Upton <email@hidden>
- Date: Tue, 11 Sep 2001 02:05:32 -0700
Part II
Well. I am confident that the Lab profile describes the outer bounds
of the Lab colorspace. Also, the space profiles you describe should
not create values that extend outside of Lab.
Now if you were talking about 2D graphing, that's a different beast.
It is true that Adobe RGB, Ekta, and other spaces contain primaries
that lie outside the visible spectrum. In the familiar Yxy
horseshoe/chromaticity diagram you can see the points of the triangle
extend outside the spectrum locus (visible light region). This is one
of those grudgingly-accepted situations where we have the ability to
make up imaginary colors and the benefit is that we can create a
triangle (at least a triangle in Yxy) that encompasses the gamut of
our favorite images. These profiles should still not render colors
outside of Lab though. IMHO.
Incidentally, I was listening when the discussion of custom space
generation in CT went by. It's on the wish list.....
I like the idea of using ColorThink to answer this question
by mapping the image data in 3-D.
<snip> So, if I understand this correctly, if there are reds that
I'm capturing
in that red wing of my scanner space, I can't tell from the 3-D Grapher
because they have already been shifted into the Lab space
is order to be graphed.
This needs a little clarification. Esoteric discussions about Lab not
capturing the entire range of visible colors aside, there should not
be colors in our world (in our perception) that are not captured by
Lab. Therefore moving things through Lab should not attenuate the
gamut. This writing is starting to remind me of my structured logic
philosophy classes at the old alma mater. Also important to realize
is that just because we can reach a conclusion logically, it does not
mean it's true.
Enough bansh!
I guess what I am trying to say is that there may be some colors out
at the edges of Lab that are not encodable by Lab but I think we are
beyond splitting hairs. Gamut maps are wonderful things but, as I am
often reminded, it is what happens inside that gamut that really
counts. There, I said it, in public too! (just wait until you see 2.0
though...)
So the question remains. Am I capturing reds that are not surviving
the conversion to Lab?
no (see how easy it was for me to shorten that answer?)
I hope I have not confused too much. Thanks for using the tool and
pushing the limits (literally).
Regards,
Steve Upton
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