[argyllcms] Re: "Calibration" scheme
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 24 Jan 2020 10:19:58 +1100
graxx@xxxxxxxxxxxx wrote:
I stumbled on an article on DICOM, here :
It's quite impressive, technically. Especially the part regarding
"allocating the available JNDs" to the 8-bit 256 "drive levels". The way I
understand it, the idea is to make each of the 256 levels result in a
"constant" JND.
As I understand it, the main aim of DICOM is to allow the reading
of medical imaging. Which is not necessarily what most people use
their displays for.
I'm not about to embark into DICOM-calibrating my monitor but I though it
"confirmed" some of my own intuition on the subject. So, instead of using a
JND, why not use a unit of L* value?
Yes, that idea has been around for a long time. You can target
an L* type curve using the dispcal -gl option:
<
https://www.argyllcms.com/doc/dispcal.html#g>
Note that the calibration only has effect for non color managed
applications. When things are color managed, it's the source
profile that determines how incoming device values are going
to be interpreted.
Also note the reservations about linearizing display reproduction
curves in general, if the precision of the Luts is limited and/or
the displays native reproduction curves are reasonably perceptually
linear. i.e. when the aim is to profile, you _may_ be better off
not compounding more quantization error.
Cheers,
Graeme Gill.
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