It seems that most maps that show British territories or former colonies are marked with red or pink. I was reading this Wikipedia article here about Cecil Rhodes and it mentioned that even a century ago British possessions generally were marked in red or pink. What is the reasoning behind this?
Red is commonly associated with the British Empire (uniform colouration, flags, etc.), but it was hard to read details on british territories since the black text clashed with the red. So it was a printing trick to lighten the colour to pink, so it was more legible.
Just the general colour associated with that empire. France was blue, Spain yellow ect.