Re: Monitor White Point Confusion
Re: Monitor White Point Confusion
- Subject: Re: Monitor White Point Confusion
- From: Refik Telhan <email@hidden>
- Date: Tue, 05 Mar 2019 00:12:02 +0300
- Thread-topic: Monitor White Point Confusion
Hi Lou,
The answer to your question:
"But, when you soft proof, with the Paper White box checked, shouldn't the soft
proof look the same on a 5000K and a 6500K MONITOR?"
No, they will not look the same, The paper white simulation is "relative to
your monitor white point". EIZO ColorNavigator or X-Rite's i1Profiler's monitor
profiling modules offer validation against CMYK standards. At the end of the
validation, the measured value of paper white for FOGRA39 verification can be
reported to be very close to 95,0, -2. But do not let this measurement mislead
you. This is only true "relative" to the monitor white (native or any other
monitor white that you have picked) which now serves as the 100, 0, 0
reference. You can set the white point of calibration to any temperature in the
5000 to 6500 K range and after every calibration/profiling round the validation
may tell you that Patch # 63 (paper white) of UGRA/FOGRA Media Wedge v3 is
measuring within a deltaE(2000) less than 1 against 95, 0, -2. But in absolute
terms the simulated color on the screen is different every time. In the
verification module of DisplayCAL, you can switch "Simulate whitepoint" and
"Relative to display profile whitepoint" on or off to measure the actual color
of the monitor white.
Soft proofing heavily relies on the adaptive capability of the eye. Just try to
find the color temperature that is right for you using a proper light box and
the print substrate that you frequently use. And this pick will only work for
your eyes. Recently, I have calibrated a monitor at 100 K increments in the
4800 to 6500 K range. Next to it was a desktop viewer with fresh lamps
illuminating a sheet of FOGRA39 compatible print stock. The whole screen was
simulating FOGRA39 paper white in Photoshop. Going through the profiles one
after the other, my colleagues have asked 6 different people which color
temperature gave them the best match. No two picked the same temperature. As
the monitors create the illusion of white by using 3 narrow band emissions at
blue, green and red regions of the visible spectrum. One monitor, as a light
source, may have a CRI value of 37 (3 very narrow band emission) and the other
may have a CRI value of 93 with no gaps in the spectral emission curve. In
fact, I repeated the test with this high CRI monitor and more people agreed on
the color temperature that gave the best match. Monitors are very different
from each other, you may find very different display panels in monitors of a
certain brand.
Best regards,
--------------------------------------------------------
Refik Telhan, EE B.Sc.
Light and Color Management Consultancy
Aydogdu Sokak 12A, Tarabya Mahallesi
Sariyer, 34457, Istanbul, Turkey
Mobile: + (90) (532) 426 21 87
--------------------------------------------------------
On 04.03.2019 19:40, "colorsync-users on behalf of Louis Dina"
<colorsync-users-bounces+rtelhan=email@hidden on behalf of
email@hidden> wrote:
I have some confusion on the selection of white point when calibrating my
monitors.
I have always used Native White Point and had good results with my Dell
Adobe RGB LCD monitor. A good monitor to print match is important to me.
The Native WP on this monitor is around 5700-5800K, which works well with
the somewhat neutral to warm papers I print on.
I know that an image displayed in Photoshop without an active soft proof
will be mapped to monitor white . So, a monitor calibrated to 6500K will
display cooler than a monitor calibrated to 5000K.
But, when you soft proof, with the Paper White box checked, shouldn't the
soft proof look the same on a 5000K and a 6500K MONITOR? As I understand
it, two "conversions" occur. The first conversion is from the document
working space to the printer profile. Then a second conversion occurs from
the printer profile numbers to the monitor using RC rendering. If neither
Black Ink or Paper White boxes are checked, the simulation on screen
ignores paper color and weak blacks. But, if Paper White is checked,
shouldn't the paper color and reduced dynamic range appear the same on
monitors that are calibrated differently. That doesn't seem to be my
experience. I'm assuming that the monitor profiles accurately characterize
the current calibration of each monitor.
I'd prefer to calibrate to 6500K, but I find my prints always come out too
yellow because I am adding more yellow to my image on screen to compensate
for the cooler display. When printed, the warmth of most of my papers
results in skin tones that are too yellow.
What am I missing?
Thanks, Lou
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