In a message dated 5/29/03 11:29:04 PM,
classicrendezvous-request@bikelist.org writes:
>> If they are using a mixing station from PPG, Dupont, Sickens, RM
>> they can match anything.
Unfortunately, this is not true. These machines only have good luck with opaque, single-layer paints. If the paint has a tinted transparent topcoat over a colored basecoat or primer, they fail (often miserably) to get a good match. The main problem is trying to analyze a color that is not really a single color. When you have a tinted overcoat, the color mix changes depending on the angle of view. Even a few degrees can make a huge difference. On a bike, where the tubes are curved, you are not seeing one color but a whole range... for example, as you approach the edge of the tube and your viewing angle gets more oblique you are seeing an increasing percentage of topcoat color and less base coat.
So if you scan a color that is, for example, a transparent ruby topcoat over a white primer, you'll be scanning thru the red at 90 degrees and your final (single) color, as read by the machine, will be way, way too light.
I love technology, and these machines do have their place, but the only real way to reproduce some colors is to trust an expert like Joe, Jim or Brian and let them match it by eye and experience.
Bob Hovey
Columbus, GA