I was wondering where the tradition of making playing cards red and black, and four symbols came from. Why not just black (or red, or any other colour) and four symbols, or no symbols and four different colours?
Bonus question: How did the ace come about? It's the odd-ball of playing cards.
On the colors: Black and red inks were the cheapest. Black ink was made my mixing soot (Carbon black) with linseed oil, and red ink by mixing powdered cinnabar (Mercury sulfide) with linseed oil to make ink. Cinnabar is a mineral dye, so it is doesn't break down or fade over time on exposure to light. Also, red stands out well against the white paper and the black regular ink, and the copper compounds needed for colorfast blues and greens tended to be more expensive, or weren't oil-soluble.
I'm not sure about the ace though.
Just for clarification, why do you call the Ace (value of 1) the oddball of playing cards?