Somewhat off-topic, but...

While I haven’t handled a whole lot of passports in my life but I have worked a bit with color models in both print publications and web design. Perceived color is a ‘slippery’ thing. When I look at something with only my right eye, I ‘see’ a slightly different hue than when I look at the same thing (under the same lighting conditions) with only my left. The perceived color (or colour) of scanned or photographed images presented on screen depends on a host of variables including lighting, the equipment used to capture the image, the equipment used to portray the image, settings applicable to both, the background context of the image, and the viewer’s ‘perception’ - my loose term for the rather complex interaction between the eyes and the brain.

The standard issue U.S. passport isn’t just ‘blue’, it’s ‘navy blue’. More like an indigo that in certain lighting conditions will appear to be closer to black. If a standard and a diplomatic passport were scanned on the same device at the same time, I daresay you would be able to perceive the differences in the two when looking at them side-by-side. Viewing either one, in isolation, against a white background, may well make the dark blue seem to look like black. Also, viewing the same objects under sunlight or even artificial ‘white light’ rather than on a screen would almost certainly reveal their color differences.

If you want to know more, look up ‘gamut’ as it applies to color reproduction and perception.

My brand new passport is definitely Navy Blue.