Have you ever redecorated a room in your home and discovered that the end result isn't quite what you imagined? This is because light can have a transformative effect on colour. The surface that you are painting will also affect how light is absorbed and colour reflected.
Glossy surfaces reflect light and obscure colour, whereas dull surfaces absorb light, often making colour appear deeper and rooms calmer. Another thing to consider is contrast. Rooms with only a few windows but which get a lot of sunlight can prove a bit of an onslaught if you paint them with deep colours. Deep colours on the walls will increase the contrast between the windows and the walls. Your eyes might find this play between light and dark a challenge or, on the other hand you might revel in it. For some, dark walls in bedrooms, can create the effect of an alluring, cosy retreat.