[argyllcms] Re: Capture One Profiles
- From: Elle Stone <l.elle.stone@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 9 Jul 2013 11:36:28 -0400
I haven't examined the source code for other raw processors. But the
dcraw command line raw processor requires white balance information
before interpolating a raw file.
The white balancing takes place *before* the interpolation. Here are
the steps dcraw uses up to the point of interpolation, quoting from my
article "dcraw C Code, Outlined and Annotated"
(http://ninedegreesbelow.com/photography/dcraw-c-code-annotated.html):
Read in command line options specified by the user
Identify the camera make and model
Get “noise floor” & “full well” information
Get camera coefficients
Calculate camera input primaries from camera coefficients
Fix pixels on user-supplied “bad pixel” list (optional)
Subtract user-supplied dark frame (optional)
Perform wavelet denoising for luminance noise removal (optional)
Scale raw file values with “noise floor”, “full well”, & white balance
multipliers (each scaling value can be left at the default value
(which is roughly D65) or specified by the user, "-r 1 1 1 1" gives
unitary white balance)
Correct chromatic aberration (optional)
Interpolate the raw file (user choice of interpolation method,
including 2 options for raw output)
So you see, the white balancing is done before the interpolation.
Kind regards,
Elle Stone
On 7/9/13, Nikolay Pokhilchenko <nikolay_po@xxxxxxx> wrote:
> IMHO about white balancing while RAW to RGB conversion: I think there is no
> white balancing during RAW conversion if the result is not color managed by
> the converter. It's just normalization. The normalization to some "standard"
> image state when typical white in RGB-image is about R=G=B. This
> normalization is not necessary in general.
> In color managed workflow the RAW conversion should be done all the same way
> as while shooting the target. I.e. without "balancing". White balancing
> should be done after application of camera profile, in color space not in
> device space. But I didn't know at the moment how to change WB of image with
> camera profile by means of ArgyllCMS? How to apply certain chromatic
> adaptation to the image in known color space?
--
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