Lighting is a very important factor in the colour of a room. Natural light will show the truest colours, while incandescent light will bring out warmer tones and yellows, and florescent lighting casts a sharp blue tone. Before deciding to paint your entire room, paint a sample block of different shades on a wall. You can even paint a sample on more than one wall to see how the colour changes depending on light that falls on that wall. Before making your final decision on the colour you want for the room, check colour different times of the day, with the lights on and off. This will ensure you make an informed decision on your colour.