[argyllcms] Re: ArgyllCMS V1.2.0 has been released

  • From: "Alastair M. Robinson" <profiling@xxxxxxxxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 03 Aug 2010 20:38:58 +0100

Hi :)

On 03/08/10 14:17, Graeme Gill wrote:

but a perfectly operating
gamut mapping will simply adapt to the different shape and map to the same
destination gamut. ie. the gamut mapping tends to cancel out changes
introduced by the change in the viewing conditions.

Oh I see - so the fact that using -cmd -dpp instead of -cmt -dpp caused the mapping to lighten midtones was actually a side-effect? I'm guessing the CAM mapping lightens midtones with respect to the black point, while the gamut mapping darkens them in response to the change in source gamut, but in previous versions the former effect was greater than the latter effect, causing an overall lightening of the image? And now the balance is reversed, causing -cmd to darken the image.

My speculation would therefore be that V1.2.0 shows less difference
> because the gamut mapping is more accurate than V1.1.1 :-).

In which case, may I respectfully request an option to bake a gamma adjustment into the perceptual table?

As it stands, if I generate a profile for an inkjet on good quality glossy paper with a really dark dense black, I end up with prints that are (admittedly subjectively) considerably too dark under "typical" indoor lighting. Skin tones in particular end up looking a bit muddy.

That's always been the case, but I've so far been using the -cmd -dpp trick to counteract it. This method has (or had!) the advantage of not messing with the colorimetric table.

Yes, the performance change is unfortunate, but my priority was to "do
it right", and worry about performance another time.

Fair enough :)

All the best
--
Alastair M. Robinson

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