Articles: Monitors
 

Bookmark and Share

(1) 
Pages: [ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 ]

Natural Color Expert and Calibration of XL Series Monitors

The SyncMaster XL24 and XL30 allow to load the calibration data right into themselves.

The calibration software must be able to use this opportunity, of course. Fortunately, an X-Rite Eye-One Display 2 calibrator is included with the monitors. This model should be familiar to people who professionally work with color. The calibrator comes with Natural Color Expert software.

The Eye-One is a small device that can be hung on the monitor’s screen (you could see a photo with the calibrator in action earlier in this article). It is secured in place with the USB cord that is thrown above the monitor as well as with multiple suction cups placed in two rings on the screen-facing surface of the calibrator. The suction cups cannot hold the calibrator without the USB cord. Their purpose is to ensure tight contact between the calibrator and the matrix.

In the center of the calibrator there is a photo-sensor (a few sensors, to be exact, each behind a filter of certain color). The calibrator has a strip of soft porous rubber around its perimeter that prevents stray ambient light to get to the sensors.

Natural Color Expert software replaces the native software of X-Rite calibrators and is meant for Samsung’s XL series monitors only. You won’t be able to use the calibrator on other monitors with this software.

When you start the calibration process, the program displays black, red, blue, green and white squares under the calibrator. There is no progress indicator – you can only see the petals of the flower moving next to the Reading Monitor caption in the bottom right corner of the screen. The whole process takes a few minutes only. When it is complete, you can remove the calibrator from the screen.

Alas, this description makes it clear that the calibrator performs only two out of the three functions discussed in the previous section of the article. It corrects color temperature and measures the color gamut. Although the Eye-One is a full-featured calibrator with its native software (i1 Match) and can determine and correct the shape of the gamma curves, Natural Color Expert does not offer such functionality, perhaps due to a licensing agreement with X-Rite that allows to sell this rather expensive tool together with monitors at a low extra charge.

So what is the purpose of writing correction tables into the monitor then? And what is the purpose of using a calibrator with cut-down functionality?

Talking about the extended-gamut monitors in the previous section, I mentioned ICC profiles and how they can be used with user’s applications for such monitors to work properly. The XL series monitors offer another opportunity. They can emulate any color gamut smaller than their own one.

The first mode of NCE is called Calibration. It allows to change any basic setting of the monitor save for color gamut. You can calibrate the monitor for specific brightness or set a desired value of color temperature or gamma. You can even calibrate a few monitors in such a way that their colors were identical. If you just select the same settings in the onscreen menus, there would be difference due to the variation of parameters between different samples of the same monitor. The calibrator helps minimize this difference.

When the calibration is over, you see a window with the results of the measurements: the coordinates of the vertices of the color gamut triangle, color temperature and the deflection of white from the desired level (in Delta E units), brightness and level of black (the contrast ratio is the ratio of white to black or 121/0.11=1100:1 here). When you click the Save button, an ICC file is created in the folder C:\Windows\system32\spool\drivers\color. This file is bound in the system to the current monitor. Any program that supports color management can use this file to get valid information about the monitor in order to correct images accordingly.

What if the application you use cannot use ICC profiles? You can switch into the Emulation mode then.

There seem to be no difference from the Calibration mode but look at the top of the screenshot: there is now a string with the path to the ICC file. This is not a file for saving the results of measuring the monitor’s parameters into. Instead, NCE will set the monitor up according to the parameters of that file.

You can also specify the target parameters without any profile: just type in the coordinates of the vertices of the color gamut triangle into the appropriate fields.

Suppose you use an application that only works correctly with sRGB monitors. In this case you just load a standard sRGB profile into the Emulation mode and launch the calibration process.

After that NCE will ask if you want to write the result into the monitor. If you answer yes, you will have your extended-gamut monitor provide hardware emulation of the standard sRGB color gamut that can be evoked with a press of a button.

The XL series monitors offer five emulation modes:

  • Custom: the user-defined settings are all available; the color gamut is maximum; brightness is regulated manually; there is no emulation of anything
  • sRGB: the color gamut, brightness, gamma and color temperature are set in compliance with the sRGB standard
  • AdobeRGB: the color gamut, brightness, gamma and color temperature are set in compliance with the AdobeRGB standard
  • Emulation: the color gamut, brightness, gamma and color temperature are set manually in the appropriate section of Natural Color Expert
  • Calibration: brightness, gamma and color temperature are set manually in Natural Color Expert; the color gamut is the monitor’s maximum one

Interestingly, although the sRGB and AdobeRGB modes are set up at the factory, you can reset them with the calibrator to correct certain flaws or the deviation of the monitor’s parameters that may occur with use. To do this you must load a standard sRGB or AdobeRGB ICC profile on the Emulation tab of Natural Color Expert. When the calibration is over, the program will suggest that you save the result into the appropriate mode of the monitor.

From a practical point of view, the Custom mode gives you access to all the monitor’s settings that you can change whenever you want but it is the least accurate mode in terms of color reproduction. sRGB, AdobeRGB and Emulation allow you to emulate two standard and one custom mode with a limited color gamut if images cannot or should not be corrected on the software level for displaying on the extended-gamut monitor. The Calibration mode helps achieve the most accurate color reproduction in applications that can work with the monitor’s color gamut and can correct images according to it.

The last tab in Natural Color Expert is where you can manage your ICC profiles. You can also measure the current parameters of the monitor (without creating a profile or changing any settings), enable a scheduled warning about the need for recalibration and reset the settings of the sRGB and AdobeRGB modes to their factory defaults (if you changed them as I described above).

So, here is the summary of what Natural Color Expert can and cannot do together with the Eye-One Display 2 calibrator and SyncMaster XL20 monitor:

  • It allows to set the monitor up for a desired level of brightness, contrast ratio, color temperature, gamma and color gamut, creating an appropriate ICC file.
  • It doesn’t allow to correct the shape of the gamma curves.

Is the last item important? It depends on how neatly the gamma curves are set up originally and if they need any correction. You will see this shortly.

 
Pages: [ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 ]

Discussion

Comments currently: 1
Discussion started: 11/01/08 10:17:50 PM
Latest comment: 11/01/08 10:17:50 PM

View comments

Add your Comment