How to find constant luminance? Photoshop LAB disagrees with, DigitalColor Meter, and looks wrong
How to find constant luminance? Photoshop LAB disagrees with, DigitalColor Meter, and looks wrong
- Subject: How to find constant luminance? Photoshop LAB disagrees with, DigitalColor Meter, and looks wrong
- From: tom lianza <email@hidden>
- Date: Tue, 31 Oct 2006 23:09:24 -0500
John,
You seem to be confusing the meaning of L* and luminance. They are
related, but certainly not equivalent. For instance an L* of 48 would
correspond to a white normalized L of about 16.8 in a linear system
scaled 0 to 100. The example that you gave indicates that the the
Digital Color Meter is returning the value for a gamut mapped color.
The display probably cannot display a=127, b=-127 that you asked for so
it has to be mapped into a displayable color . It's clear that there
are a number of color management steps that are going on here.
With regard to your goal, there is a solution, but it involves a number
of numerical translation. Basically you need to map LAB->XYZ->RGB. Take
a look a bruce lindblooms site: http://www.brucelindbloom.com That
would be a good place for you to play...
Tom Lianza
Video and Motion Picture Technology
X-rite corporation.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden