Setting LCD monitor RGB channels before profile?

I’m trying to profile/calibrate a Dell 2707WFP 27" LCD monitor with ColorMunki, and not getting the best results. A test B/W gradient shows banding and some cyan-magenta casts. I also needed to push the Brightness control to zero, and the Munki still wanted it to go lower… didn’t leave me with a warm and fuzzy feeling!

The monitor does have access to it’s RGB channels, but the Munki does not provide any way to help adjust them. It is my feeling that PRIOR to profiling a monitor, the profiling system should allow a “linearization” or neutralizing the unit. I’ve also heard that the only real adjustment on an LCD monitor is the brightness and contrast of the backlight. If so, what did they bother putting access to the RBG channels on this unit? Just a sales gimmick?

A contact in Switzerland is using this monitor and set it up with his “…trusty X-Rite DTP94”. And was able to get very excellent results, and was able to linearize it.

It appears the Monaco Optix XR Pro is the same as the DTP94. I’m considering returning the ColorMunki (and losing the print profile capability for now), and getting an XR Pro. I can live with factory profiles for the Epson 3800, but would like to get this monitor tuned up as good as it can get. I on OS X 10.4.11 with a Radeon 9600 XT vid card.

Two questions:

A: Is it a correct concept that the RGB channels should used to set the LCD to produce a neutral gray before starting any profile?

B: Does XR Pro provide a way to linearize the RGB channels before beginning the profile cycle?

Here are my thoughts to your 2 questions:

A. If there was adequate control over the RGB controls, then yes,
possibly you could use these to produce a neutral gray. But this isn’t
the case… in reality, it’s quite a different story in practice than it
was on a CRT. These RGB controls are not direct but indirectly created.
Secondly, the only data that you will affect (without a true hardware
DDC calibration) is via the video card. Tuning the LUT data is the key,
and that will be facilitated by the calibration/profiling software you
are using.

B. The DTP-94 is just a device (a very good one and better than most),
but it controls nothing. You still need a software that communicates
with the device and it’s detection of the LCD’s response, and then
linearizes that data (gray balances) and sets the LUTs correctly. If
the correction is too much, you will experience some banding.
Practically though, if you’re using Native White Point, the correction
should be minimal.

The best package we have found to control gray balance (for most LCD’s)
is ColorEyes Display Pro. There is a bundle for $319 that includes the
DT9-94 device too.
<http://www2.chromix.com/colorgear/shop/productdetail.cxsa?
toolid=1122&pid=10449>

One more thing… this topic is the very topic discussed by Pay Herold
of CHROMiX in the upcoming ColorNews Issue #31. If you don’t get this
newsletter, you can subscribe to

Please do check out past ColorNewsletters as we do post a technical
article in each issue and archive past issues at:
http://www2.chromix.com/ColorNews/?pid=10449

Hope that helps.


oRick Hatmaker, CHROMiX Worldwide Technical Sales
o Toll Free 866.CHROMiX extension #7
owww.chromix.com
oColorGearColorThinkColorValetColorSmarts Maxwell


On Apr 18, 2008, at 2:58 PM, Harrzack wrote:

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Also, it’s Pat Herold, not Pay Herold (although many customers do pay
him homage). He heads up our Technical Support department and writes
good articles too. It must be a Monday.

Rick Hatmaker
CHROMiX

On Apr 21, 2008, at 5:42 PM, Rick Hatmaker wrote:

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