No place else say this. But don't believe that young guy that claims that "precision weighing equipment " wasn't available until recently, and that there were no paint standards until the "latter half of the 20th century."
Paint components were mixed by multiples of the Pound or the Gallon, not some silly microdrops, and standard weights have been around for centuries.

As for standards, he needs to go to a library and look up books by guys named Archer or Elliot or something,,,,,they show and document Standards back to the beginning of US aviation,,,,,not "after 1950"

I'm going to continue to go with the guys that retired from the Smithsonian on this, and not some youngster doing a blog for clicks.