Another question to ask yourself before going to the paint store is whether the room to be painted feels too small or too large? Using the right color paint can create the illusion of a more intimate room or a more open one.
The same room painted in a warm yellow color gives the impression of a smaller space than one painted in a cool green. Warm colors advance; cool colors recede to the naked eye. So if your room is overly large, paint it in the red, orange, or yellow spectrum and in the blue, green and violet spectrum if it's small. Notice the blue ceiling paint in the receding example. A light, pale blue gives the feeling of more height.
The last question to ask yourself before buying paint (scroll down to see the other issues you should consider) is whether you find the room unpleasantly dark during the day. If the windows in the room face north or if you live under a canopy of trees, the wrong wall paint may not do well in dim light. You can help keep your electrical bill down by choosing a pale (lots of white in the formula) hue and one from the red, yellow, or orange families like in the first example on the right. This will make the room brighter/warmer during the day in spite of the lack of light. If you prefer cooler colors, choose a pale one that has warm undertones. In the second example I illustrated, I choose a blue-violet which is warmer than a blue-green. It's critical to test your paint on the actual walls before committing.
