[fermienrico]

>> Google Glass said that they initially all thought red would be good, but after trying different colors the consensus was that it was terrible

They should have looked at a larger sample size. Red is used in rangefinder viewfinders for over 30+ years. Leica M240 has red and white as options. Red is by far the best from all standpoints - contrast, legibility and versatility.

Red dot sights are used in firearms and they are also by far superior to any other color.

I am doubtful of Google engineers and whether they put enough thought into exploring colors by using a larger sample size or cross checking different industries.