This is why everyone used to Pantone color books back in the day for printing (and I knew some guys who used them for paint mixing). You just call someone half a world away with the right code and get the color you wanted...

Lee - True. For printing. If you have a match or a “close enough” to a swatch number, you can have the swatch scanned. The hard part is getting access to a swatch book. I work with printers that have them. It seems they’re priced per pound like gold, though. Even if you order a swatch from Pantone, they’re not as cheap as you’d think.

Heck, we've even got color charts in the horticultural industry as well but I don't think they'll help all that much with paint... LOL

http://rhscf.orgfree.com/

The problem is the Pantone system does not have enough colors, and there is no way to specify "half way between 105C and 106C." I know, I have a Pantone book and I've tried. Sometimes you get lucky and one swatch will be a spot-on match, but if not...

A better system for our purposes would be Munsell, https://munsell.com/ which has a lot of earth tones, but NOBODY has access to the Munsell swatches to do the initial match.

Munsell and other color standards will give you a good start. But keep in mind that different equipment, software can and will give you different results, sometimes on the money, sometimes off the mark. Not everyone uses the same equipment. That’s why it’s best to have a sample and get a good scan and have it tweaked by your supplier and then consider the 10’ rule for the real world.

On the computer, using 16 bits per each red, green, and blue channel produces a total of 281,474,976,710,656 different colors. I think I'll stick with just the actual paint chips for now.

In my 1954 DuPont catalog, WE5562 matches REO Truck Yellow, 93-71369, and WE5569 matches 93-1021, an unassigned fleet orange.

Since I really didn't have to cover the oranges too extensively in my Reading thread, here are all the cards specifically labeled as "Orange" from the 1972 Chevy fleet fan deck. 082 Omaha Orange seems to be missing but many manufacturers tended to use that one as a standard production color around that time. 014 Imitation Gold is all the way toward the lower left...

I saw this IRM car on Ebay. Older photo.

Looking at the small stenciled numbers, I see they were changed.
Why would they re-rate the car? What could be some reasons?

CAPY 88000
LD LMT 89200
LT WT 52700??

The short answer is: Any time a car hits the shop for repairs, modifications or a rebuild, it gets weighed. That’ll change your empty weight or “LT WT” which can affect your capacity and sometimes the load limit. If you notice, to the right of the LT WT stencil, there is a re-weigh location and date stencil that has also been changed. That’s when and where the work was done.

Welcome to the Intercahange.