Natyashastra
तज्ज्ञैस्तेनानुसारेण कार्यं तदनुगं मुखम् । अथातो मुखरागस्तु चतुर्धा परिकीर्तितः ॥ १६२॥
The face should be made to follow that, by those who know that.The colour of the face according to the circumstances (lit. meaning) is of four kinds:
english translation
tajjJaistenAnusAreNa kAryaM tadanugaM mukham । athAto mukharAgastu caturdhA parikIrtitaH ॥ 162॥
hk transliteration by Sanscript