I am looking for an 80's fantasy film/possibly TV series. I don't have much to go on, but here we go: It's a fantasy/adventure film with possibly two children as main characters that go to another world (a fantasy world) with a witch that wants to throw them in this white tunnel thing. There are these amazing people in butterfly costumes. I remember watching Dark Crystal around the same time that I watched this movie, but it's not the Dark Crystal. If you have any ideas please let me know. I'm sorry this is so vague.

Sounds like The Great Land of Small (1987)

I think that may be it. I am so excited now. I have been looking for this movie for years. My husband even thought I could have dreamed it up lol. Thank you so much! *I found two trailers on the web. I saw the butterfly people in one and in the other they showed the rainbow that I remember. I just have to get it and make sure now. Thanks so much!

You're very welcome, hope it's the right one :)