Color is not claimed as a feature of the mark.
The mark consists of the standard wording "I GONG CHA" appearing above the Chinese characters "HUANG DI YU KE GONG CHA", with two seal shaded carriers containing the Chinese characters"YU KE" and "GONG CHA".
The non-Latin characters in the mark transliterate to "HUANG DI YU KE GONG CHA" and this means "the tea was given to the emperor by means of pay tribute" in English.
The wording I GONG CHA has no meaning in a foreign language.