[Tig] LUTs for Video File Codecs - ICC profiles

Bob Friesenhahn bfriesen
Thu May 4 16:27:58 BST 2006


--
Thanks to oktobor for supporting the TIG
--
On Thu, 4 May 2006, Adrian Thomas wrote:
> There is no 'computer standard whitepoint' as such, the closest that we have 
> to any kind of standard is sRGB, which mandates D65, and is LOOSELY 
> compatible with our TV expectations of Rec. 709.

sRGB is not so much a standard as it is a summary of results based on 
evaluating the CRT devices and viewing conditions common when the 
specification was written (early to mid '90s).  See 
http://www.w3.org/Graphics/Color/sRGB.html for the specification, 
which includes a description of how it came to be.

>> Some monitors also can't change their white points.  I believe the 
>> computer standard white point is 9300K.  Television/broadcast is 
>> D65, except in Japan.  Even after adaptation, there is a noticeable 
>> difference between

The mention of 9300K shows how much common display devices have 
changed since the analysis supporting sRGB was done.  I understand 
that LCD panels often have a natural color temperature of 11000K. 
Most computer displays are extremely bright out of the box with a 
blue-white tint.  When the "sRGB" setting is selected, the display 
then looks much more yellow and less bright.  Just as with TVs, 
consumers will almost always choose the display with the brightest 
looking picture.

Bob
======================================
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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