[argyllcms] Re: help with camera profile
- From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 25 Jul 2012 09:23:16 -0700
On 2012-07-25, at 8:29 AM, Iliah Borg wrote:
> With digital there is no simple way to get density or L* values, and
> linearization in RGGB domain does not work too well.
If you're using Adobe Camera Raw or something else that works with DNG
profiles, you can (awkwardly) create a DNG profile with a custom tone curve.
Shoot a target with known Lab values, and then adjust the tone curve until the
output matches the measured values. On a Mac at least, you'll need Adobe's DNG
Editor and the Digital Color Meter application. If, while you're at it, you
also use DNG Editor's feature to create color tables from a ColorChecker, the
resulting output is already decidedly in the ``not bad'' category. Profile
those results with Argyll, and you get great results.
RAW Developer would seem to make that process a bit easier as it lets you edit
the tone curve right there, and it gives you much more helpful pixel readouts.
What I suspect I'll be doing, at least for the time being, is creating a tone
curve that maps the neutral step patches to the corresponding RGB values for
the gamma of whatever working space I feel moved to use this week. (I've been
using ProPhoto RGB because that's been the least awful one that Adobe lets you
convert RAW to, but I'll probably move back to Beta RGB with RAW Developer.)
What I'm envisioning for Argyll is a modification to scanin such that it still
takes an RGB TIFF but then calculates the calibration curves at the same time
as it reads the patch values. You could then feed it a linear TIFF output if
your RAW developer supports such, or whatever else you can manage, and let
scanin be the one to worry about the tone curve.
Cheers,
b&
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