Re: LAB's not a good colour space
Re: LAB's not a good colour space
- Subject: Re: LAB's not a good colour space
- From: ibn Ezra <email@hidden>
- Date: Sat, 23 Mar 2002 19:03:21 -0500
'LAB' is a good thing and it has plenty of practical uses, but serving
as a general storage format is not one of them. Think of LAB as
something akin to a pedagogical device for understanding light & colour.
But everywhere, and every day you and all your devices work in RGB. Even
in when you are working in CMYK you are still dealing with the
interaction of light (RGB) and ink (CMYK). The moment that light source
in your scanner comes on, you're dealing with RGB.
On the other hand, 'LAB' is a theoretical model developed to provide a
'vocabulary' for precisely communicating colour. The ICC system
incorporates the scientific basis that the various LAB flavours provide
as a foundation. So in essence, when you use RGB & a valid ICC profile,
you are getting all of the advantages of LAB... without actually having
to make the conversion.
While a valid device profile provides the unadulterated gamut of a given
device, for practical reasons many folks choose to settle on a standard
RGB colour space (typically AdobeRGB) for the sake of simplicity. In our
studio, for example, we have 9 designers with varying levels of managed
colour sophistication and it was agreed that the purpose of managed
colour was to help simplify the arcane art of getting good colour on
press. So it was decided that we would work in AdobeRGB.
While converting to AdobeRGB might result in a gamut that is smaller
than the device's native RGB gamut, we felt that was a compromise that
was well worth making. If you were building some kind of 'digital
master' archive this would not be a good compromise... instead you would
want to capture the native gamut of the device with a valid device
profile (RGB). So once again, LAB offers nothing that can't be done with
a good device profile in RGB.
Finally, there's no point in capturing the areas of white noise that
reside beyond your scanner's gamut by choosing a larger profile. This
file would almost certainly have to be converted again in the future to
account for the gamut of your output device (no matter how 'good' it
might be). How can this be better than converting directly from your
scanner's profile to that of your output condition?
hope that helps,
-iE
On Saturday, March 23, 2002, at 04:56 , Andrew Rodney wrote:
on 3/23/02 12:44 PM, gvido trepsha at email@hidden wrote:
Then, what is it that capture device captures?
Every scanner and digital camera on the planet captures RGB. Profile that
and you have the widest gamut the device can create anyway. You don't
need
to convert at this point, the preview in ICC savvy applications like
Photoshop are correct. There is something to be said about converting
to a
well behaved RGB Working Space but you don't have to.
For archiving purposes?
Raw RGB from the device with a profile is the rawest, unaltered, widest
gamut archive you can get.
................................................
ibn Ezra
mailto: email@hidden
................................................
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.