[argyllcms] Re: Dell U2711 - is it any good?

  • From: Rishi Sanyal <rishi.j.sanyal@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 22 Jun 2011 11:03:48 -0700

Graeme Gill wrote:
"To get an accurate result using a ccmx you need at least
the spectrometer, the colorimeter and the display, and you get an
accurate correction for just that serial number colorimeter."

Exactly. So why they market their new colorimeters, that don't include
a spectrophotometer in the packages, as items that "ensure unrivaled
color accuracy and consistency now and in the future" is unclear to
me. Looks like pure overzealous marketing hype to me. You could say
the same thing about colorimeters already on the market now. With a
spectrophotometer, even they can (somewhat) accurately profile
wide-gamut displays (in my experience anyway).

-Rishi

On Wed, Jun 22, 2011 at 7:40 AM, Knut Inge <knutinh@xxxxxxxxx> wrote:
> What is the problem that (monitor) calibration tries to solve? I would
> guess "the fact that the precise perseptual response for a given
> display input is unknown, and for some applications, e.g. image
> editing, there is a need to know what the user is seeing". The reason
> why it is unknown is because display manufacturers generally do not
> share the ideal/new response of their products in a machine-readable
> format, and because 2 identical, new displays may have somewhat
> different response, a third identical display may have another
> response after years of (ab)use, and a "cold" display may differ from
> a "warmed up" display.
>
> If we had an instrument that correlated perfectly with human visual
> system, it would be easy. Connect it, calculate the error, and feed
> back some correction. Such instruments do not exist.
>
> I am a bit lost when you say that a single monitor+colorimeter
> correction matrix can be used to correct future measurements. How can
> one know that the "unknown stuff" that makes monitors/colorimeters
> change over time and over production runs, does not also make this
> correction invalid? Are there known knowns and known unknowns?:-) May
> one assume that the spectral response of each primary is constant (and
> can be baked into a correction matrix), while the flat gain of each
> primary is fluctuating and should be calibrated every once and again
> using a colorimeter and correction matrix?
>
> Thank you for your time enlightening me
> -k
>
>

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