White point for LCD.
White point for LCD.
- Subject: White point for LCD.
- From: "Mark Rice" <email@hidden>
- Date: Wed, 18 May 2005 13:47:33 -0400
I can adjust the white point on my Dell Ultrasharp LCD from 4500K to 9000K
as measured by the eye-one. I have to adjust it to about 5900 K to get it to
visually match a 5000K light box from GTI.
By the way, today I was at the On Demand printing trade show in
Philadelphia. In the Kodak both, a Kodak technician ( unnamed for now) was
showing off Kodak softproofing with an Apple Cinema. It appeared that the
softproof was good, except that the white point appeared to be about 6500K
next to the GTI light box at 5000K. The technician claimed that Kodak color
profiles altered the white point to be correct, but that the overhead lights
in the convention hall altered the display so that the white point appeared
blue. I didn't want to argue with him.
Mark Rice www.zero1inc.com email@hidden
Date: Tue, 17 May 2005 16:56:08 -0600
From: Andrew Rodney <email@hidden>
Subject: Re: Eizo Calibration/basICColor with GAMMA L*
To: Marco Ugolini <email@hidden>
Cc: ColorSync Users Mailing List <email@hidden>
Message-ID: <BEAFD2A8.FEAE%email@hidden>
Content-Type: text/plain; charset="US-ASCII"
On 5/17/05 3:55 PM, "Marco Ugolini" wrote:
> When it comes to measuring a display's white point, it does not matter
what
> the luminance is, or the contrast, or what profile is driving the display:
> the white point remains the same.
Not quite. The white point is a measure of the color of white. We can try
and define it, adjust to some white point we prefer etc. With LCDs one
usually measures it and since there isn't anything we can really do to
adjust it (at least "physically" as we could with a CRT), we leave it alone
and record what it is. The luminance is how bright this is but it's separate
from the color of white. So a display at 120 cd/m2 versus one at 110 cd/m2
is the intensity separate from the color. Does this mean that as one changes
the intensity, the white point might change? I guess it could be that's not
something we need to be concerned with since the profiling software should
be looking for and recording these values.
> Or are we talking here of an uncalibrated and unprofiled white point such
as
> what appears at the beginning of a calibration/profiling routine? (That
> would be the "native" white point, I guess, with perfectly linear LUT
curves
> in the vcgt tab)
The term Native white point is usually used to describe the white point of
the display "as is". In many software products, setting this is saying
"record the white point, leave it alone since (with an LCD) there isn't
anything we can really do with it). Of course you can ask the software to
attempt to calibrate to a CCT like 6500K or better an actual color such as
D65 and an adjustment has to take place, usually at the graphic card which
many want to avoid.
Andrew Rodney
www.digitaldog.net
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden