[robo]

Had the same problem with paint colour match against a gel colour and it took a couple of goes to get right.I was kicking off at the paint supplier about it when the paint rep came in and he explained that the only way to get a good match would be to give him a sample < an off cut of the grp>to get spectrum analysed. Came back with the perfect match so it can be done.

The tints are added by weight and if the paint supplier does not move much of a certain colour that tint will become more concentrated over time which is where most of the colour mismatches come from.

Bob