21 C.F.R. § 82.2051
(a)
(2) Specifications.
Ether extracts, not more than 0.5 percent. Soluble chlorides and sulfates (as sodium salts), not more than 3.0 percent. Intermediates, not more than 0.2 percent.
(b) Each lake made as prescribed in paragraph (a) of this section shall be considered to be a straight color and to be listed therein under the name which is formed as follows: