On my About page, I make brief mention of the blue feather icon. The feather is not actually blue but rather the blue is an optical effect, a visual illusion.
Turns out, the Morpho butterfly, common in butterfly exhibitions due to it’s vivid colour, uses a similar trick.
In another angle on blue, it took 3 decades to figure out how to make blue LED lights (I don’t mean blue tinted covers). That discovery netted a Nobel prize. By producing the final primary colour, we could make LED & LCD TV’s, smart phone screens, light-based water sterilization, and the blend that creates true white light. Lights and screens have never been the same.
And yet another blue; shorter frequency blue lasers allowed the development of higher density storage. This allowed vastly more data to be stored on a standard optical disc, including HD movies (Blu-Ray).
And of course, we associate blue with Sadness, as personified in the movie Inside Out.
Blue is a key aspect of our window on the world.