So, you've decided on your sign type, and you're going for something to be mounted outdoors and you want it illuminated.  Now, the question is exactly what type of lighted outdoor sign do you want to go with?  It's not just one choice, after all!  There are some different choices when it comes to the type of lettering used, and the lighting you have to pick from. What type of material is the letter being mounted to? It is important to consider this when choosing the type of sign you are mounting on your building. Is the surface porous? If it is, you may want to consider a channel letter that is internally illuminated.                 If you are looking for a halo-light sign, or reverse channel letter sign, you may want to add a backer to create a surface the light can bounce off of.         Channel letters  are 3D letters that are internally illuminated by LEDs or neon tubes.  They normally have the front covered, but this can be left open to show off the internal lighting.  They can also have the lighting directed backwards from the letter for the above halo effect.