Originally Posted by
Medic Zero
Side by side, the white reflective tape is clearly a little brighter than the red reflective tape of the exact same type, from the same manufacturer/batch.
White is considerably brighter than any of the colors -- the color filtration is purely absorptive, the colors that get blocked aren't re-emitted as some other color, they're just blocked. Red tape reflects only the light hitting it from the red end of the spectrum, the rest is absorbed.
For example, see 3M's specs for 983 "Diamond grade" reflective tape for the difference in coefficients of retroreflectivity. Yellow is a little bit less efficient than white, but red is much lower.
http://multimedia.3m.com/mws/mediawe...-&fn=PB983.pdf