No worries on the Necro post. The thing with purple, is that it is a bit of a pain. There is not one resistor that will get the perfect purple. Several people claim to have imitated OSPP but they haven't really. They've found a resistor that gives them a purplish color under a certain set of circumstances most of the time. The trick to OSPP is that it is the exact purple that I like (my favorite color) and is calculated each and every time. There is variety in power sources, drivers, and the LEDs themselves that make it impossible to say...OK you need a 1/2W 15ohm resistor (for example). It completely depends on what batteries you are using, how the LED is driven, and the LED itself. We have found, even on our stunts where we use the same LEDs and the same 3AAA batteries and even the same type of battery there is still variance in the exact resistor to achieve the perfect purple. We use a potentiometer and calibrate the resistance on each and every purple saber we do. We keep drawers filled with resistors :D. If you don't want to go through all the rigamarole with the potentiometer, the other option is to just try a handful of resistors and pick the best one (which is what most people do). :)
