For those playing along at home, and because I might as well stop torturing poor Diego:
The fact that any given color produces the same perceptual impression every time you see it is what "dispersion-free". If the same stimuli produce different perceptual impressions at different times, that is "dispersion".
If every color produced a different perceptual impression, then color perception would be "veridical". The fact that it is not means that our color perception is "non-veridical"
Interface theories of perception are dispersion free. The same stimulus produces the same perception. This is what you need to make science and engineering work. Interface theories of perception need not be veridical. It doesn't matter if you see "green" as a color or a smell or a looming beast, as long as you reliably perceive it the same every time. Dispersion-free, non-veridical. It works fine.
As for you, Diego, look up the definition of dispersion in the paper. Download it, search for the word "dispersion" and you will find precisely the place in the paper you're asking me to show you. As I have suggested repeatedly. Dispersion is precisely the concept you've gotten wrong all along, when you're bothering to argue from a coherent position at all.