Been covered a few times - most recent in a rearend marking discussion in the 67-8 section
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I use few colors right out of the containers but instead mix them together to get a match to the original color. Also depends since your only doing a single car where I might do a dozen or more over a period of time.
An earlier related thread
http://www.concoursmustang.com/forum/index.php?topic=6144.msg35109#msg35109Basic colors such as black, bright/strong red, orange, tan or white can be something like Testor's but if you get into marking drivelines or some spindles then a couple or more bottles will be needed.
Krylon school bus yellow is pretty good for some of the bright yellows and a Meadowlark Blue that can be used for some of the light blue marks, Testor's makes a lavender that is a decent match for the lavender used in many markings. There are some that are just OK IMHO so I take a base that is close and add to it. The more the better (I will normally go through it at some point) and you don't want to run out half way through because another mix will likely be off no matter how much you try.
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From a Shelby paint mark discussion
Your not often going to match something right out of the bottle or jar and it depends on what you have to mark. Some colors or parts will take allot more than other and if you try and match you want to mix allot more than you'll need for the job - since if you run short you'll never get a really good match the second time. Don't this for 25 years and made that mistake too many times
For your (single car) usage The yellow will be used in a number of areas so would suggest not getting the really small jars like Testors instead get a pint of Rustoleum.. They make a strong yellow that can be used in a number of areas (tie rods, center link, pittman and idler as well as the front springs)
For the tan you might just be able to get by with one brown (they even make a tan but its not always easy to find) and one white Testor model enamel and mix both together in another jar to get something that looks like a light tan or matches what you found. If you have a nice example.
IMHO going to be a better purchase than using the Corvette colors over at Quanta
Buy some cheap brushes at Harbor Freight - 1/2 and acid brushes. Apply the paint to the coil springs without loading the brushes up fully and keep the brush flat (don't follow the coil around) so that it produces a noticeable brush (jagged) end in the direction of travel .