18% Grey

18% grey is the colour that most colourists paint their suites, it's because its a perfect neutral mix of RGB. It takes a lot of time to train your eyes to colour an image properly, but one of the first things to do is to minimize the amount of colour pollution around your image. The less colour pollution around a photograph the better you'll be able to see what the photographer or cinematographer was going for in terms of their colouring.