Why has my soap gone from green to yellow?

Qusetions: i've just began producing melt and pour soaps. I produced some xmas trees which i naturally coloured green. But right after two weeks they've turned pure yellow. Does any person know why?? make sure you, as i've produced these for presents. i've so far as i realize utilised the appropriate colouring? thank you.

Answers:As it aged has your soaps pH altered? a lot of colourings are pH sensitive