Thank you. Very helpful! Excellent question and first-rate answers. (2018/07/04)
Both "light orange" and "bright orange" seem to be accepted as qualifiers, but these are not synonyms (in my view). Light orange refers to pale orange, whereas bright orange refers to intense orange...
Why not ανοιχτή πορτοκαλί to make it feminine? If it were green we'd say η φούστα είναι πράσινη right?
Because 'πορτοκαλί' cannot be inflected, so it is considered neuter, I guess.