Suppose you're in love with the color blue, and you wish everyone who came to the wedding would wear one shade or another of it. Can you ask people to?
It seems a little pushy -- talk about a control freak, right? Then again, putting "black tie" on the invitation is perfectly acceptable.
What do you think? Put your comments here, and see my answer after the jump.
None of my etiquette sources rule on this, so I had to do a little pondering. And to be honest, I'm still not completely willing to accept it as polite.
Even a request ("please wear blue") may feel a lot like a command; few of us want to disappoint a bride on Her Big Day. And unlike, say, guests at a Halloween costume party, people can't just decide to stay home if they don't want to participate. They don't want to miss out on such an important occasion just because they already have a tan suit instead of blue seersucker.
"Black tie" or "casual" gets written on invitations as a service to guests -- not to dictate what they wear, but to clue them in so they won't feel under- or overdressed. And it leaves the field wide open in terms of fashion or color choices.
There is also a weird "control freak" vibe. If you do decide to try this, please don't explain it by saying, "It'll look great in the pictures"; that seems sort of selfish. Say instead, "it'll give the wedding a wonderfully festive feel."
It's best not to put such a request the invite itself -- it's too complicated to fit into the "black tie" spot on the lower right. Use a reception-card insert and verbiage such as, "We invite you to join in the wedding's color palette by wearing a shade of blue."
What do you think? Are you making a request like this for your wedding?