Phil
my thinking. Red color when spraying.
color depth or intensity lets one know how much has been applied to the surface. spraying the inside of our egg shells with a color close to the color of the
fiberglass would be hard to tell where you have been
yellow, is used used in industrial mechanical spraying, it is controlled by settings
I never hand sprayed large surfaces with a yellow. I have bought gallons and quarts; all yellow, hand painted or rolled.
I have only seen red contact cement in 5 and 55 gal. drums for work shop spraying