[argyllcms] Re: Profile input white not mapping to output white

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 27 Nov 2012 11:52:38 +1100

Iliah Borg wrote:
> Before demosaicking, that is before some form of recombination of raw 
> channels, we do
> not have colour information at all. We need to run recombination / 
> demosaicking to
> calculate two missing components for each pixel. Raw channel data is some 
> form of
> monochrome, recorded as shades of grey so to speak.

Hmm. You don't need full resolution data to do a white balance, and
yes, you have color information- you have the camera filter
RGB values from the raw cells. Each cell is a point sample out of it's 2x2.

("Demosaicking" is all about trying to invent detail
that wasn't actually captured, and it generally shows if you
look at the pixels. A downsample by 50% to the actual sampling
interval always looks a whole lot better in my view. It all
seems to be numbers game, driven by marketing. If displays were
rated the same way as cameras, they would magically increase the
numbers of pixels by 3, without an visual change ...)

Graeme Gill.

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