I used to use the lyson print guard back when I did the dirty digi inkjet thing. It worked well enough, but doesnt make the prints bullet proof, the surface is still quite fragile, but not as much as it would have been without it. It didnt leave any kind of surface sheen or anything - that stayed as matt as it was before. Mind you, that was all 7 years ago, so the formula or product might have changed a bit since then?
As for the colour ... what is this "Colour" thing you speak of?