If you want to make this a religious question, or if it is a religious question for you, you should definitely not wear the other colour for a funeral.
On the other hand, seeing it as a ceremony to send off a close person, you might be able to wear also navy, grey, dark grey or even something colourful, if for example it was their wish.
Whatever it be, it should be respectful to the deceased - it shouldn' be anything they wouldn't approve. But also respectful for other people present. In other words, a buddhist shouldn't go to christian funeral in white and vice versa.