[Tig] wide gamut display/distribution in practice?

[Bob Friesenhahn]

On Sun, 29 Oct 2006, glenn chan wrote:
>
>
> I'm curious as to how the wide gamut systems proposed in DCI and the new
> HDMI spec (1.3) compare to Rec. 709 HDTV.  It seems like the future is
> headed in this direction and will be relevant for anyone doing grading for
> digital cinema and potentially the home theatre market.

I have not read the HDMI 1.3 spec and don't know about alternate 
mappings it may provided for wider gamut.  What I do know is that it 
supports 10 and 12 bit RGB and YCbCr (4:4:4) to 1080P/60 as well as 
1080P/24.  From my point of view, existing display systems still do 
not adequately reproduce the already defined gamut range.  HDMI 1.3 is 
an excellent step since it provides one component of the solution 
needed to support professional grade video reproduction in the home.

DCI specifies colors in X'Y'Z' space (i.e. all the colors that normal 
people can see) so by definition it can support the full gamut range. 
However, existing display devices do not support the full gamut range.

> 1a- In a well-implemented system, how much better does wide gamut look?  Is
> the difference significant?

I can't not answer that since I have yet to see a sufficiently 
well-implemented system.  All the consumer systems I see suffer from 
banding, compression artifacts, and problems with dynamic range. These 
reproduction problems tend to dwarf the gamut issues.

Given the problems with existing consumer systems, I tend to think 
that advertising support for a wider gamut is a red herring from the 
product marketing department.

> 1b- In practical implementations, are there any downsides to wide gamut
> systems?  (i.e. inconsistencies in mapping out of gamut colors)

A major downside is that studio monitors do not support it.  If you 
can not see what you are doing when editing in wide gamut then there 
is no point to use it.  You could be creating a bloody mess and not be 
aware if it.

Similar to the fact that water flows down hill, wide gamut needs to be 
introduced in the studio first.  It makes no sense at all to introduce 
wide gamut in consumer devices first.

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