[argyllcms] Re: printer profiling best practice

  • From: Anders Torger <torger@xxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 10 Feb 2015 09:55:25 +0100

Thanks for the information.

This means that if having as much shades as possible is more important 
that absolute accuracy (which it generally is for fine art printing) it 
would be an advantage to have more test patches located near the gamut 

If that is the case it would be nice to have a weighting parameter to 
targen so you could do such an optimization.


On 02/06/2015 05:36:20 AM, Graeme Gill wrote:
> Anders Torger wrote:
> Hi,
> > I have a question though. One opinion I've come across more than
> once 
> > when reading all over the 'net is that profiles made with higher
> patch 
> > counts produce "better highlight detail". Not in relation to argyll 
> > specifically but X-rite profiling software.
> > 
> > I was assuming that a low patch count did not impact detail, but
> only 
> > accuracy.
> But accuracy may translate to highlight detail. I'm presuming that
> "detail"
> in this sense means shading detail rather than spatial detail
> (sharpness).
> If, for instance, a device has a saturation curve characteristic as 
> it
> approaches white, then coarse sampling of the colorspace may result
> in a profile that is inaccurate near white, and may then accidentally
> map near white values to white, so you loose highlight detail.
> A more detailed sampling may better capture the device behaviour, and
> allow
> the profile B->A to properly map near white values to near white,
> retaining highlight detail.
> > A theory I've come up with how that could be true though is that
> with 
> > more patches you sample more of the gamut surface and get a more 
> > precise definition of it's boundary, and thus you could get a tiny
> bit 
> > extra detail towards gamut clipping. Is this true?
> Not for output devices. Typically the gamut is defined by the
> device space range limits, so there is no issue with measuring
> colors at the gamut edge.
> But in white is typically at the gamut boundary, so inaccuracy near
> white
> will (by "coincidence") imply less accurate knowledge of the gamut
> boundary.
> Graeme Gill.

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