On "Company" letterhead, write to FERRO Color Corp. in Los Angeles, Cal. and request "evaluation samples" of their color pigments. Ferro makes oil based color pigments in a CONCENTRATED, thick paste form. The Phthalo-Blue & Phthalo-Red are beautiful, the Ferro-Green & Ferro-Yellow are also great. At a company where I used to work we used 55 gallon drums of the Ferro-Green & Ferro-Yellow. We'd use 1 gallon of the Ferro-Green per 5000 gallon batch of Polyurethane Elastomer, and it would come out a nice light Lime Green color.
I personally have mixed Ferro-Green with Rustoleum Aluminum paint and have spray painted everything from steam boilers to forklifts. Even painted one of the old cruddy company pickups a beautiful Emerald Green. When I got done they thought we had gotten a "new" truck. LOL