What makes fluorescent colours so bright?
Normal colours reflect a maximum of 90% of the available light as their colour. However fluorescent colours can reflect up to 300% of their colour, making them appear so much brighter.
Fluorescent colours use special pigments in their inks to absorb light outside of the visible spectrum and reemit them as light that the human eye can see.
This is what makes fluorescent colours appear brighter than conventional colours.
Here are some technical details
Skip this if you don’t really care why fluorescent colours are so much brighter.
If you do care, this will be interesting to you…
Humans can see a very narrow range in the middle of the electromagnetic spectrum, known as the visible light spectrum.
This image helps to show how little the human eye can see in the whole spectrum: