[Openicc] MS on HDR CMS :)

[Chris Murphy]

On Feb 11, 2008, at 2:23 AM, Kai-Uwe Behrmann wrote:

> Am 10.02.08, 22:52 -0500 schrieb Chris Murphy:
>> Nevertheless the ICC needs to deal with HDR. And Europe needs to get
>
> What else would you like to see supported?

CAM. This one size fits all thing doesn't work when it comes to HDR,  
and although ICC v4 and PRMG helps, it's still one size fits all.  
It's not scene specific.

>
>> over this recent obsession with L* image encoding, which I think is
>> weird. With respect to encoding the article makes a good point. For
>
> What is wired in respect to the L* encoding for LDR images?

Print doesn't have an L* based tone reproduction curve. For near two  
decades it's been known that it's closer to gamma 1.8 defined.

The ECI explicitly recommends users with 8bpc ECI-RGBv1.0 (TRC=gamma  
2.2) images *NOT* convert them to ECI-RGBv2.0 (TRC=L*) because of  
loss of quality, i.e. the lost of bits. ECI is really recommend it in  
a 16bpc workflow, *and* primary for the print and publishing  
industry*,in which case we shouldn't even be having an encoding  
debate! They aren't 16bpc workflows in print and publishing, and L*  
is not an appropriate TRC for them either.

So quite frankly I wish ECI-RGBv2.0 would die a fast painless death.  
I am still a big fan of ECI-RGBv1.0 and actually prefer it over Adobe  
RGB (1998) for 8bpc print workflows, and I continue to recommend it  
for that. But L*? 12% loss of bits in the conversion through 8bpc.  
Why would I do this?


Chris Murphy
Color Remedies (TM)
New York, NY
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Co-author "Real World Color Management, 2nd Ed"