Re: Setting default RGB in OS X 10.4? (and Nikon Capture)
Re: Setting default RGB in OS X 10.4? (and Nikon Capture)
- Subject: Re: Setting default RGB in OS X 10.4? (and Nikon Capture)
- From: Rob Galbraith <email@hidden>
- Date: Thu, 05 May 2005 14:54:59 -0600
Hi Rich,
I've heard back from the lead developer of Nikon Capture. Here's what I
learned:
Much of the crunching of the linear RAW data is done in the camera's RGB. I
took this to mean that most or all of the obviously RAW-related settings,
like Color Mode, impact this portion of the RAW data's processing.
But, that's only half the story of Capture, since it has a number of
Photoshop-like image editing tools that aren't intended to work way back
down the processing chain to the RAW data. He cited, as examples of this,
its Curves, Color Balance and Photo Effects functions, which work within the
RGB colour space chosen in Preferences (or in the colour space linked to the
chosen Color Mode if the "use this instead of...." checkbox isn't checked).
Since I principally use Capture to prepare files for conversion using the
controls on the Advanced RAW palette, and not too much else, I hadn't given
much thought to how processing of its more-standard image editing functions
would be integrated under the hood. What he says makes sense to me, then, in
terms of how the processing of a single image happens in a mix of the
camera's RGB and standard colour spaces, given the different types of RAW
and non-RAW image editing controls the program has.
So, everyone's right here it looks like :-).
-Rob Galbraith
PS: The Color Mode settings change the colour appearance of photos more
dramatically than could be accomplished with tone response curves. Not sure
if you were using tone response curves as an example, or if you were
suggesting that that's the difference between the Color Mode settings, so I
wanted to clarify the point.
Also, in v4.2.1 of the program, at least on my computers, the Color Mode
popup entries are no longer labeled with a colour space, as was the case in
the past (I didn't notice which revision of the app intro'd this change).
Now, as far as I can tell, the main/only place (outside of prefs and the
save dialog) to see the RGB colour space that the photo will be saved to
(and in which part of the processing is done) is in the Information
palette).
>
> I believe Erik is correct. I used a whacked, blue profile as the input
> to Capture. The image appears whacked even while editing it, before the
> image is saved in any way, indicating that the image has been encoded
> into the input profile colorspace. In fact, this whacked image can
> then be saved ( and converted) to CMYK, and the system default CMYK
> profile is used and embedded at the time of saving, indicating that the
> image went into the wacked default RGB profile first, then was
> converted to the default CMYK profile.
>
> The "Color Modes" appear to act in essence as 5 different Camera RGB
> profiles (e.g., different tone response curves) that are used to
> convert the image to the preferred RGB profile space. The RGB color
> space used will be either the one selected in Prefs, or is none is
> selected there, sRGB is used for 4 of the five Color Mode settings, and
> AdobeRGB is used for the fifth, to be determined by the Color Mode
> setting, as labeled. When the CM pref is not selected (the usual
> case), the Color Mode setting determines both the rendering "look" and
> the editing/output profile.
>
> Either way, the editing does not appear to be done in a Camera RGB
> space, with a conversion to the output space occurring on Save.
>
> --Rich
>
> Rob Galbraith wrote:
> "But, I'm not sure about your description of the encoding, or colour
> space
> handling, part of Capture's workflow. As I understand it, Nikon digital
> SLR
> cameras and Capture work the same way - all processing is done within
> "Camera RGB," or rather the RAW data is run through colour matrices and
> 3D
> look up tables and tone curves that aren't operating within an
> output-referred ICC colour space like Adobe RGB or ProPhoto RGB. Then,
> as a
> final step, a conversion to a colour space - as set in either the
> camera's
> menus if it's a JPEG, or as set in Capture's CM prefs if it's a NEF -
> converts the image data from Camera RGB to that chosen RGB or (in
> Capture
> only) CMYK colour space."
>
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