Below is the formula I found doing a search on the forum. It is from 2005 and I took it to the Sherwin Williams shop and they said Violet is not a pigment that they use:
Sherwin Williams pigments and using a Martin Senour "Bright Life" Latex Eggshell Enamel, Neutral Base (Qt.):Black: 22/32Does anyone have a revised formula for JBL blue? I'm repainting a pair of 4301B's.
Blue: 1 oz + 16/32
Red Oxide: 1/64