jonwvara 

I can't tell what colors really look like based on a little color chip. Next time I'm going to have a frame painted, I'm going to go to a big shopping center parking lot somewhere and look around at new-looking cars until I find a color (or maybe more than one) that I really like. Then I'll take a digital photo of the whole car, take it to the chevy or Honda dealer or whatever and get them to identify the color based on the model and year.
I've never done that but it sounds better than guesswork.
jv

deez

thats how I did it. I brought my frame to a Body shop and said "Paint it the same color that you paint Cream color Mini Cooper's"

and Thats what I got.

Ex Pres 

Sounds good, but you don't have the large panels on a bike like you do on a car, so the paint still won't look exactly the same.

And you can change the shade of the color coat in subtle ways by using a different color primer.

RobbieTunes

Yes. "Ducati red" seems to make most shops nod in agreement.

And some clear coats have a yellowing effect, also.
I can't tell, but that's what the painters tell me.

All I know is, I turned in a Cinelli frame, said "Ducati red" and he's got it.

Ex Pres 

Porsche Red, also called "guards red", is another favorite. Use red oxide primer. Over gray it takes on just a little orange tint.

jgedwa

In a related theme, make sure to paint all your bikes the same color so no one is ever really sure how many bikes you own.

jim

repechage

Many vehicles for some time have an ID plate (label) on the driver door or jamb that will include an exterior color code, this is better than taking an image, if you can get access to the the label.

Some cars such as Audi, the "same" color will actually be unique, based on what mfg. plant the car was actually assembled at. For subtle tones as found in some metallics this can be dangerous to match without that info. There is a Scion color that is almost impossible to match, its a "best to repaint the car" situation.

As stated earlier, tubes are not panels, the scale can play tricks. For the most part for me European metallics are finer grained, which suits tubes better, coarser metallics as seen on some Chrysler and a few Infiniti models would look pretty red light district on a bike.

RobbieTunes

Paint codes on cars generally represent a "range" of hues within that number. For example, a Chrysler white number can still have a range of whites that correspond to that number. For years, the body shop used a color wheel, eyeballing, and trial and error to match paint, generally by shooting at a damaged panel until they could not tell they'd painted. Even the best efforts didn't always get a great match. Throw in metallics, pearls, and it just gets a lot worse.

Add in market forces and free enterprise, and you have Dupont, PPG, and other paint suppliers making the same colors for the auto industry, and each is a little different.

Digital technology and the market moved a lot of the matching problems to the paint supplier. Cameras can analyze a color and come up with a recipe that matches better than most humans. I have seen the cameras spec out a Honda red for a Ford pickup, and the match be perfect.

Pantone numbers also make a difference. Colleges, for example, have pantone numbers so that items, decor, etc made for them and their fans are the same color. I wanted to offer a bike painted in college colors for a charity auction, and part of the permission process, besides getting NCAA licensing permission, was to guarantee the correct pantone.

repechage is correct, the coarser metallics don't "bend" well, but there are "candy" metallics being used on custom motorcycles that correspond well to the vintage Schwinn Sting-rays and road bikes.

The pearls are likewise very distinct. A Cadillac pearl and a Lexus pearl are two different animals. The mica and other substrate particles used to create pearl effects are different. The purple fade 1988 Ironman has a pearl in the white that would wash out on a car surface, but looks great on the bike. It's just very hard to duplicate.

A metallic paint good for a car, again, can look pretty crappy on a bike. Often, the clear coat alone can give the effect desired on the bike.

This is a great thread, and there are some real bike refinish experts on this forum. I am not one of them, but I hope they continue to chime in.