Hi, There is an option to select an area in UFRaw to be used for white balance.
There is no command line option to apply your own RGB values from the command line. The way to do it would be to create a UFRaw ID file with the relevant numbers. But, the RGB values you are getting from the JPG image are not directly relevant for applying to the raw image. The JPG image already had some white balance correction applied to it. There is also a color matrix that mixes the raw channels to get the RGB channels, a gamma curve and other corrections. These make it very tricky to translate the JPG values you are getting to raw channel multipliers. Udi On Wed, Sep 30, 2015 at 6:49 AM, Alan Corey <alan01...@gmail.com> wrote: > I've been doing digital photography (amateur) for about 15 years but > finally bought a Nikon D5200 so I can have RAW files. I've been > programming on and off since 1968, got introduced to graphics through > doing scientific plotting. I'm a retired network administrator, still > program for fun, mostly in C. I have a Color Munki and I've read > quite a bit about having everything calibrated. > > The current Ufraw homepage at http://ufraw.sourceforge.net/ says it's > going to get into more detail later about color matrices but as far as > I can tell never does. > > The only photography text I ever read cover to cover is Mastering > Photographic Composition, Creativity and Personal Style by Alain > Briot. He's a big fan of using gray cards, Macbeth color charts, I > have great hope for white plastic lens caps but I don't have one yet. > The idea being that white balance needs to be more dynamic than > manufacturer presets like cloudy and incandescent. When I use the > cloudy setting the pictures are too yellow, then again there are dark > clouds and light clouds. > > I wrote a program that takes a JPEG shot of a gray card and outputs an > averaged hue and RGB values. Because it might not be full frame or > there might be a thumb holding the card I do: Take an overall mean > hue, calculate a standard deviation, then a second mean hue of pixels > within 1 standard deviation of the mean, then mean RGB values for > those pixels. It's just a command line thing, the only dependency is > the common JPEG library. > > What I'd like to do is output numbers that can plug into Ufraw's > channel multipliers and green and temperature settings. Those 5 > numbers seem linked in ways I don't understand yet. I don't like > using the eyedropper to sample a neutral area of the real image > because it assumes there is one. There also doesn't seem to be a > provision for using a full-frame shot of a gray card and applying the > numbers to a different image. > > -- > Credit is the root of all evil. - AB1JX > > > ------------------------------------------------------------------------------ > _______________________________________________ > ufraw-devel mailing list > ufraw-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/ufraw-devel >
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