higher pressure = lighter
lower pressure = darker.
I never had much luck with the scanners.
I get better matches since I switched to a brand that has
color chips for the alternates within a paint code.
That's the main reason I don't use DuPont Chromabase anymore,
I love Chromabase, most user friendly base out there, but my
supplier uses the VIN no of the car to pick the alternate to
mix the paint by, and that doesn't always work.
Especially if the paint has faded.
With my present brand, matching the color chips to the actual car
gives me a choice, sometimes of several variants.
I usually get really close, after that, for a perfect match you have to
blend into the adjacent panel. Even the clear affects it.