Spectral tools - Graph
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Use the Graph tools to measure the spectrums of color patches (Reflectance mode), displays (Emission mode), and light sources (Ambient and Flash modes). (Note: As with all CT&A Spectral Tools, an Eye-One Pro is required. Also, some Eye-One models do not support all measurement modes).
The screenshot above was obtained by measuring Sample-1 (S1) in Flash mode and Sample-2 (S2) in Ambient mode. Depending on the samples measurement mode, various operations can be performed, either on a single measurement or by combining two measurements. If your requirement is to formally assess the quality of a display or viewing environment, such as a light booth, then you should also have a look at the ISO 3664+ tools shown in the next screenshots. Returning to the top screenshot, the sample on the left (S1), drawn in black in the top graph, is a measurement of a small digital camera accessory flash. The flash Illuminance was measured at 813 lux-sec; its color temperature is 6156 K and its CRI, calculated using D61 as a reference, is 96 (this reference is shown between parentheses below the CRI). The bottom graph of the same screenshot shows "S1 vs Illum.", where the S1 spectrum is reproduced and compared with the spectrum of an ideal D61 source of the same brightness, shown in green. We see an excellent match between the spectrums for wavelengths higher than 430 nm. We could have made a similar comparison between the S2 ambient measurement and the 2800 K blackbody used as a reference for the CRI by selecting the "S2 vs Illum." button. The sample on the right (S2), drawn in red, is a measurement of a common tungsten-halogen desk lamp. With a 2789 K Correlated Color Temperature (CCT), this lamp has a spectrum very close to Illuminant A; it has a definite yellow tinge compared to D65, the nominal display white point from which this screenshot was taken (in other words, the "xy" coordinates of the lamp, 0,4535 and 0,4102 in the screenshot, fall in a yellower area of the chromaticity diagram when compared to the coordinates of the D65 Illuminant). Its Color Rendering Index (CRI) is 99 when computed using a 2800 K blackbody as a reference. The image below is an example of what is obtained by clicking on the "Save image" button located in the bottom of the Graph tools dialog. The image can be saved at two resolutions, 1X, as shown below full size, or at twice the resolution and size (2X) for better printing quality.
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