HP DreamColor Z31x User Guide - Page 71

Warm-up mode To facilitate a bulk calibration workflow where multiple monitors will be calibrated or recalibrated in a single session, the display includes a standalone warm-up mode. This mode allows you to warm up multiple monitors without connecting them to a host computer. The display is warmed up at the luminance specified in the active color preset. To enable standalone warm-up mode: 1. Connect each display to a power source and ensure that the master power switch on the rear of the display is in the On position. Depending on display configuration, the display may immediately power on when the master power switch is activated. 2. Turn the display on, if necessary, and then off again using the power button on the lower right of the bezel. This first power up boots the internal hardware, while the power off again puts the hardware to sleep. 3. Using the buttons on the lower right bezel, hold the top bezel button down, and then press and release the bottom bezel button. After the bezel lights turn on, release the top bezel button. The display enters warm-up mode and begins to cycle between full-screen white, red, green, blue, cyan, magenta, and yellow. If an active source device is connected to any of the display inputs, burn-in mode will turn off and be replaced by the source's output. If the source is disconnected, warm-up mode resumes when the source is no longer present. NOTE: To disable warm-up mode, turn the display on and off using the bezel power button. Backlight stabilization after luminance change The display's backlight operates in an "analog-style" DC mode, which means that the voltage to the LEDs changes as the front-of-screen luminance changes. As a result, there is a period of backlight stabilization required when switching from one luminance setting to another. This can impact calibration accuracy, If, for example, the display was warmed up at a 250 cd/m² luminance and a calibration was requested with a luminance of 100 cd/m², the white point calibration could be off by as much as 2.0 ΔE 2000. The backlight needs time to stabilize at the new luminance level. Measurements performed with the PR-740 spectroradiometer show that the white point accuracy is within 0.002 CIE xy after 10 minutes at the new luminance level and within 0.001 CIE xy after 15 minutes. For best results, HP recommends that you allow the backlight to stabilize at the desired luminance prior to calibration. One way to achieve this is to calibrate to the desired luminance, wait 10 to 15 minutes, then calibrate again at the same luminance. The second calibration will be far more accurate than the first. For this same reason, if switching between presets with dramatically difference luminance levels, wait at least 10 minutes before making color critical assessments. User calibration methods User calibration is the process of specifying the calibration targets (primaries, white point, gamma/EOTF, and luminance), and then instructing the display to calibrate to those targets. There are three primary methods for user calibration. ● Using an on-screen, menu-driven calibration procedure This option provides basic calibration choices and is suitable for single-user calibration when standard color space primaries and gammas/EOTFs are desired. An option to recalibrate an existing calibration is also available. ● XML-driven calibration using StudioCal XML This option provides the greatest calibration flexibility because it allows you to do much more than a standard calibration. StudioCal XML functionality includes the following: User calibration methods 61