Re: [Openexr-devel] Color Management Proposal / Siggraph meeting

[Chris Cox]

At 6:13 PM -0700 8/13/04, Florian Kainz wrote:
> I guess I should have been more careful about the wording of the
> section on painting:
>
> In the proposal, we suggest that all OpenEXR images live in the color
> space that we call scene-referred.

> Several people had asked how one
> would paint a scene-referred image.  One possibility is to make the
> paint software aware of the proposed color management scheme.  In this
> case all image manipulations happen in scene-referred space; in order
> to display the image, the paint program continuously applies the SROM,
> OMRD and RDPD.

Yes, that's pretty much what needs to be done.


> The example where a primitive paint program saves images in a file
> format where pixel values correspond more or less directly to screen
> frame buffer values was meant to illustrate that this case can handled
> in our scheme:  Even if all you have is an image that lives in the
> display's color space, you can derive a scene-referred image from it.
> The example is not meant as an attack on Photoshop or on any other
> software with built-in ICC profile support.

I didn't see it as an attack, but it is a mistake that a lot of 
people make (not taking any color management into account and 
assuming everything is based on the display values).


> Our color management proposal is meant to work in a film and video
> production environment, where ICC profiles have, for whatever reason,
> not been successful.

Usually a lack of knowledge (of the ICC spec., of math, of color, or 
of human vision in general).


>   I don't really care whether the concepts described
> in the proposal describes are a subset or a superset of ICC profiles
> (I think they are neither).  The proposal attempts to address problems
> specific to film production.

But why invent another format for describing the same information?
Especially when your version won't easily interoperate with other 
workflows and other applications?  (yes, I could write a translator 
for yours to ICC, but not for ICC to yours)
I think it would be better for everyone if you worked with the ICC to 
improve their specification to better address HDR (again, I think 
it's mostly minor changes needed), and then have a standard that can 
interoperate, and for which many tools (software and hardware) 
already exist.


There's a conference in Scottdale, AZ that you should attend: 
http://www.imaging.org/conferences/cic12/
The CIE and ICC will both have meetings around this conference, and 
all the color experts are usually there.

Chris