David,check out www.photonlight.com,there are some good facts on the lights there. The Photons vary not only in color but intensity ,beam width,and battery duration. The white has a very wide beam,it almost looks like a flourescent light when shined on objects. It`s range isn`t too great though and since it`s a dual battery light(blue and turquoise are too) it has only a 14hr battery life. Blue and turquoise also have wide beams but not as wide as white. Turquoise has a better range than white or blue and it`s really pretty(women love this one!). The blue tends to make things appear a bit blurry I think due to blue lights focal length. Turquoise isn`t as bad. Yellow has a very narrow,bright flashlight type beam with good range. I`m carrying one of these now. Orange`s beam is a somewhat wider and still very bright. As soon as my new order comes in I`ll be switching to orange and giving the yellow to my wife. Orange also has good object definition. Red has the best definition and saves night vision better than the others but isn`t as good for illumination outdoors and such. It`s good for reading maps,in car use etc. Green has a fairly wide beam,object definition isn`t bad,range is okay,not too hot for use outdoos in the woods etc. where everything is green. Best battery life of the bunch,up to 7 days! Standard Photons are good for 5 days. The above observations are based on trying all the different colors very briefly myself and getting input from customers the website address has charts etc. that go into more detail. It`s Brian Avery`s site,I bought my first Photon from him. His prices aren`t bad and the service was fast. Some of the other dealers are selling them for just over what I pay for them wholesale! They must be buying zillions of them to get those prices. Marcus