The color of the light has nothing to do with how hot it gets. The difference comes in the wattage of the bulb and wether or not there is a reflector that amplifies the light or not.

Red lights are better because they disturb your snake less, but as far as temperature is concerned it shouldn't matter red or blue.

Your snake needs one side of the enclosure to be between 88 and 92 degrees and the other side needs to be between 78 and 82 degrees all the time. How hot is the UTH? And is it regulated by a thermostat?