All the data we've collected over the past couple of years, and all the data from the government and researchers show that very little visible light is getting down deep (more than 30 feet) in the Columbia River. So why the many different colored lures for Salmon?
Here are some examples of the quick-n-dirty LEDs we've rigged up to use to add color and visual attractants to our lures.
Basicallly, we took an LED, stuck a 3V coin battery between the LED leads (so it turns ON), then dipped it into Plast-i-Dip, the wonderful liquid plastic! We also added a snap-swivel, to attach the LED to the Lure or end of the leader for easy on-and-off. This LED has paper inserted, so the LED doesn't turn on until the paper soaks in water. Or, we can pull the paper out to make it brighter.
This one has a larger battery, to last longer. There are a rainbow of cheap LEDs out there too, and some that automatically blink.
Infrared (IR) and Ultraviolet (UV) LEDs are also available. Salmon like UV, but Sturgeon hate them all!
Good luck! Another tip - there are other ways to make light down deep in the water, and it doesn't require a battery - cool! Salmon do seem to notice voltages, but that isn't a bad thing...