Originally Posted by sparklemotion
What I don't understand is if the color hues are inherent to the device because of the way it's made, which I absolutely do believe, why are some PW's so much worse than others? Shouldn't they all be fairly similar?
With the very greatest respect, I've answered this question at least half a dozen times already. It's because the colour fringing is due to very slight non-parallelism in the two faces of the light diffuser. These are difference of the order of the wavelength of light - ie way, way below what any reasonable manufacturing tolerance can achieve.