How do you match a paint colour from the past?

Matching colors based on web images is always going to be iffy because of lighting, source camera color balance, monitor calibration, et cetera. It's also going to be tricky to match the "right" color because from what I understand finishes on original vintage fenders can evolve over time as the nitrocellulose lacquer yellows; so finding an authentic Sonic Blue color is one thing, but making it look like 50+ year old Sonic Blue would be another. http://www.guitarhq.com/fenderc.html has some interesting detective work with regards to the original colors and modern replacements. This is what is says for Sonic Blue:Sonic Blue Lacquer Source(s): DuPont 2295L. Low VOC Source(s): DuPont 2295K. Originally used on 1956 Cadillacs. This original nitrocellulose color wasn't translated to acrylic lacquer till 1996. Before the original Sonic Blue was again available from DuPont, the closest lacquer relative available was a 1958 Chrysler color, Ballet Blue, DuPont #2852L. When refinishing using Sonic Blue, I like to use a very slight yellowed tint coat over the blue to give a nice "aged" look. But be careful - too much tint and you turn this color into puke green.Googling 'DuPont 2995L' turns up some results from various Fender message boards that might be useful. Good luck!

The chart partway down http://www.guitarhq.com/fenderc.html says it's a Cadillac color and specifies the paint number...But it looks like Fender http://www.fender.com/guitars/stratocaster/classic-player-60s-stratocaster/0141100372.html#q=sonic%2Bblue&qSubmit=&start=1. Couldn't you go to a guitar shop with an iPhone app in hand?

From the husband, man of many guitars:Agree with buriednexttoyou - Reranch would probably be the most accurate out there. But if you're comparing a new finish to an actual vintage Strat, also keep in mind that the finish on that guitar has aged and changed over the years. Reranch also sells tinted clear lacquer that a lot of people use over a color to make it look aged. Or you can let it age itself, over about 20 years.

Physically matching the paint requires finding the color index number of the pigment, then looking at a graduated scale of the color from full strength to lightest tint shade. Addition of white will gray the intensity of the color. "Sonic Blue" has a pigment name (like phthalocyanine blue, for example) which is its chemical structure, and that pigment will have a color index number. If you can find out the chemical name and index number, that's how conservators match paintings. Surface gloss would also be a factor. I hope this is helpful.

Thanks to everyone for these answers - together they've enabled me to pin down pretty exactly what we need. I've realised that my original question was wrong - it's not so much about matching the colour as matching the actual paint which turns out to be quite a specialised automotive paint. three_red_balloons: The problem with sampling a modern Sonic Blue Strat is that even if we manage to locate one and assuming that Fender are still using the same paint we would have the colour but not the paint. However, your first link is great and really points out the subtleties of matching the colour as well as giving a lot of detail on the actual paint so it's really helpful both in identifying the paint and framing the question. buriednexttoyou: the restorer who is going to do the job said much the same thing and is going to mail some samples of the colour to choose from but it would be best if we can obtain the exact paint that Fender used. Guitar Reranch has matched the colour but I'm not sure they've matched the chemistry and that will affect things like reflectance and aging. kellyblah: I'm sure my sister would congratulate you in your taste in husbands :-) That's a very good point about the lacquer and general aging. The Strat in question has at some point been stripped of its original paint and is currently just lacquered wood. I think the aim is to restore it to how it would have looked when new rather than try to fake aging so the 'apply paint and wait for 20 years' option may be the way to go - we're in this for the long game! One interesting point is that because of aging differences and other variations, there may not be a single, definitive, Sonic Blue pre-CBS Fender in existence. effluvia: that was very helpful advice - I think this is more like restoration of a painting than a simple case of matching the colour. Taking your advice on index numbers combined with three_red_balloons's first link has let me track down the details we need to source the exact type of paint that was used which was DuPont Duco: 2295. Duco was a nitrocellulose lacquer: "...all General Motors (GM) cars were painted with nitrocellulose lacquer (all other car manufacturers used enamels except GM). GM liked lacquer. It dried fast, looked great, could be rubbed-out to remove minor scratches and dullness, and it spot repaired easily. Enamels looked dull in about the same time as lacquers, but you couldn't easily rub them out to get the shine back. And the dealers and body shops loved lacquer for the ease of application and drying time." - from http://www.guitarhq.com/fenderc.html I've since found some links that between them pin down the paint pretty well: http://www.tdpri.com/forum/finely-finished/392349-matching-sonic-blue.html http://www.strat-talk.com/forum/pre-cbs-strats-before-1966/109649-sonic-blue-pre-cbs-strats.html Here are two site that sell sonic blue nitrocellulose lacquer http://www.manchesterguitartech.co.uk/shop/sonic-blue/ http://www.tonetechluthiersupplies.co.uk/sonic-blue-nitrocellulose-paint-aerosol.html So, it seems that, we are closer to the 'elusive Sonic Blue' as my sister called it. So thank you for all the help - colour me impressed - and I now have a much better understanding of the intricacies of paint restoration.

(Sigh. Sorry for the late redundant reply. This was sitting in an open tab and for whatever reason didn't show that there had been any other answers.)

Hey Usonian, thanks for the effort and for the entirely non-redundant point about avoiding the puke green effect which is arguably more important than getting the right colour in the first place.