If you want to see the difference between mildew and mould then the first thing you should pay attention to is the way that it looks. Mildew is generally white, grey, or yellow and grows on the surface of moist, warm areas. It either has a fluffy texture a little like cotton wool or it will have a powdery texture. Mould, on the other hand, tends to be dark green or black. Mould grows underneath anything that has gathered any form of moisture and generally has a fuzzy or slimy texture.