Spectral tools - ISO 3664 (Color monitors)
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Based on the "Color monitors" viewing conditions defined in ISO 3664, this tool is designed to rapidly characterize your monitor "Brightness", "Chromaticity" and "Brightness uniformity". In the screenshot above, the center position is selected in the Brightness uniformity section; the absolute brightness at this position is 155 cd/m2 with a 5952 K color temperature, and the chromaticity offset is 0,009, well within the target goal. The relative brightness (in %) is shown relative to the center position (the maximum is usually the center position). By selecting another position, you could see this other position's absolute "Brightness", "Meas. Temp." (Color temperature) and "Meas. offset" (chromaticity offset). We can save all test data in a file by clicking on the "Save to file..." button. The CHROMATICITY target is a very useful tool in its own. You can select the target center amongst several standard Illuminants, including 3200 K, a color temperature often used for TV Studio lighting. The screenshot below shows how the measurement shown above is closer to the target center, with an offset of only 0,002, if we select D60 as the center (compared to 0,009 at D65). You will notice three colored diamonds around the target; these diamonds identify primary colors that need to be removed, when you are close, or added, when you are far, in order to approach the target center (these primaries are in reference to the CIE1976 x'y' Chromaticity diagram obtained with the 10 degree Observer). When these diamonds are used in conjunction with the Tuning Mode, engaged by clicking on the "Tune" button, and which automatically triggers the Eye-One at fixed time intervals, you obtain a powerful tool to adjust a display White Point. The Tuning Mode can be used with the other Viewing Conditions as well.
You can obtain a global snapshot of the test results by printing a one page report, shown below, which is useful for compliance reporting. We see that while the uniformity is good, the display brightness is minimum in the upper-left corner and maximum in the bottom-right; the brightness uniformity goal is met (90%+) but not the preferred goal (95%+). A similar report is available for all viewing conditions.
These tools are called ISO 3664 with a "+" to indicate that alternate reference illuminants can be selected by the user for each test. For example, while ISO 3664 calls for a D65 target center for monitors, many would prefer using a D50 target, as recommended in ISO 12646 (Graphic technology -- Displays for colour proofing -- Characteristics and viewing conditions); to do so, simply select D50 in the "Target center" popup menu. In our example, we selected D65 as the chromaticity target because this was the white point used to calibrate our display. We used the "Take all" button to rapidly measure the nine targets, which are displayed one by one at the locations specified by ISO 12646. You can also open an image of the nine targets and measure them manually; this is helpful when you want to measure the characteristics of a monitor not connected to the computer on which BabelColor CT&A is installed. Shown below, in reduced size, is such a target; similar targets are available in three image formats and for most popular screen resolutions in a folder named "ISO12646_targets" located in the BabelColor CT&A application folder.
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