HP DreamColor Z27x Calibration Best Practices for the DreamColor Z27x Professi - Page 13

Calibration Best Practices for the HP DreamColor Z27x Professional Display - Z7X230/Z7X240 Firmware Release | Technical white paper Using Non-Supported Measurement Equipment Though multiple measurement instruments are natively supported by the Z27x display, you may wish to use another instrument to make adjustments to an existing preset or to create another preset. Studio Cal XML supports this option via the external_primaries tag. Designed to operate similarly to the recalibration tool built into most Digital Cinema projectors, measurements are made of the native red, green, and blue primaries, and 100% white. This data is then provided to the calibration software via this tag. There are two caveats to be aware of: • As only primary and white point measurements are made with the external instrument, a new luminance target cannot be iterated. Therefore, the existing luminance value for the preset you are recalibrating will be used. • Existing calibration measurement data must be present on the display in order for gamma to be correctly calculated. In most cases, factory data or data from your most-recent calibration with a supported instrument will be sufficient. If you have updated to the Z7X240 firmware any calibration data from a calibration - including factory calibration - performed on a previous firmware revision is no longer present. This is an unavoidable side effect of the upgrade to Z7X240 as this update changes the entire memory partitioning for the display's internal processor. If this is the case on your display, you must do a calibration with a supported instrument prior to using this function. (This is not the case of new displays that shipped with Z7X240 as the firmware was installed prior to factory calibration.) Z7X230 and Z7X240 are functionally identical, with the exception of this memory partition change. Therefore it is not necessary to update to Z7X240 at this time. (It will, however, be required to update to future firmware updates when they are released. The external_primaries tag must be used in conjunction with the target_primaries tag. It contains eight attributes and is structured as follows: The attributes are identical to those in target_primaries. See page 8 for more information on these attributes. As with target_primaries, the use_uv tag is optional. Making Measurements With Non-Supported Measurement Equipment As mentioned above, you must make measurements of the panel native primaries and white point so you should switch your display to the Native color space preset. This is the last preset on the on-screen menu preset list. To facilitate primary and white point measurements, it is recommended that you use the internal test pattern generator. (External generators can be used, if desired.) The internal test patterns are not accessible by default, but one of the four bezel button function keys can be set to display the pattern generator. To set a function key to the test pattern generator: 1. Press any bezel button to display the initial button labels, then choose Open Menu to display the Main Menu. 2. Use the bezel button arrow keys to navigate to Menu and Message Control then press Select. 3. Navigate to Configure Function Buttons then press Select. 4. Navigate to the desired function button then press Select to display the list of commands that can be mapped. 5. Navigate to Test Pattern Generator then press Select to assign it to the function button. 6. Press Exit to close the on-screen menus. Now that you have mapped the test patterns to a bezel button, you can use that function to display the required patterns. First, confirm that the display is set to the Native color space preset. Then, display the red, green, blue and white test patterns, and measure them with your instrument. Record the xy or u'v' measurements into an external_primaries tag in your Studio Cal XML file. Then enter the desired primaries and white point into a target_primaries tag in the same file. 13