GRE multi-color LED
I've found that, other than primary colors, there are vast differences from scanner to scanner. I had one scanner that would display yellow beautifully, but that same code on another scanner looked terrible. I couldn't get yellow to ever look good on the second scanner.
I'm fairly happy with the 16 color combinations provided, which includes no light to white and flashing or solid. When colors don't work like yellow, then I've programmed pink (useful for medical channels) and gray (several shades).