The main use for krypton is to make light. There is one main type of krypton light bulbs. This is called a gas discharge lamp. There are three main types of these. First is a low energy gas discharge lamp or "neon light". Low energy gas discharge lights made from krypton are near white to green. Second is a high energy short length of time gas discharge light or "flash bulb". These are mostly used for photography. They are bright blue-white. Third is a high energy gas discharge light. This third kind is mostly used to light airport runways. They are also bright blue-white.