Chi (2010) proposes that 黃 was originally a pictogram (象形) and the original character of 尪 (OC *qʷaːŋ, “a disabled person with a protruding chest or abdomen”). It has been phonetically borrowed for "yellow" since the era of the oracle bone script. He (1998) noted the possible ritual of burning disabled people with a protruding chest or abdomen to pray for rain as mentioned in Zuozhuan. The 口 in the upper part of the bronze inscription of 黃 might be depicting the disabled person's face facing upwards.
Li (2012), on the other hand, proposes that 黃 was originally a pictogram (象形) and the original character of 璜 (OC *ɡʷaːŋ, “semicircular jade”) as the 口 in the oracle bone script resembles a ring of jade, so the character would carry the meaning of "a man wearing a ring of jade on his chest". The meaning "yellow" is the result of rebus.
According to Shuowen, it is both a phono-semantic compound (形聲/形声, OC *ɡʷaːŋ) and ideogrammic compound (會意/会意) : phonetic 炗(, “light”) + semantic 田(“field”) – the color of earth, with 炗 being the ancient form of 光 (OC *kʷaːŋ, *kʷaːŋs, “light”). However, this interpretation is likely erroneous as 廿 at the top was formed as a result of corruption of 口 in the bronze inscription.
Red and yellow, black and white, they are precious in His sight—Jesus loves the little children of the world. [original English lyrics] No matter red, yellow, black, white, they are all treasured in Jesus' heart—Jesus loves all the children of the world. [literal English translation]
黃宗羲/黄宗羲 ― Huáng Zōngxī ― Huang Zongxi (Chinese intellectual and political theorist that lived during the latter part of the Ming dynasty into the early part of the Qing)