The real reason why passports only come in four colors.

And, generally speaking, it’s pretty much true that countries opt for these dark, official-looking hues.

But it turns out that there’s no official regulation forcing these countries to select primary colors.

Illustration showing Blue, Green and Red Passports

Credit: Mehroz Kapadia

There are, however, no stipulations in place that dictate how a passport looks.

“Nothing stipulates the cover color,” confirmed Anthony Philbin, ICAO’s chief communications officer.

So, why the global predilection to navy blues, maroons, forest greens, and black?

Meanwhile, Caribbean states typically opt for blue passport covers.