My view is that, as long as a carp (assuming we are referring to carp) has not been caught previously on the offered bait, and provided the bait is presented in a way that THAT fish is not frightened AND provided the bait is put into an area that the fish is happy to feed from, it is not very important if the bait is highly flavoured nor brightly coloured. It is a bit like religion really, you either have faith or not! Personally I do not bother colouring my carp bait (boilies) I do use glugged hook baits though, it makes me feel better!! This subject is the proverbial, how long is a piece of string?!!!