The reason why the room was pink was because on black and white film, hues of red become dark shades of black. Pink is the perfect balance to give it that dark creepy grey.
A related fun fact: while old black and white film was under-sensitive to reds, it was correspondingly over-sensitive to greens. Actors whose characters were meant to have unnaturally pale complexions - like Morticia Addams - would often take advantage of this by wearing makeup with a green base tint in order to make their faces “pop”. This is where the modern trope of cartoon vampires having green skin comes from.
These are some fun fucking facts
Time to see the world for what it really is.
Poor, poor baby,
say you can’t help the fact that you’re so crazy,
and you’re so good at making me feel guilty
for trying to walk away ‘cause I’m tired of being mad