I've got a couple of sunflower heads that i had to chop off, coz the garden was a mess. The seeds inside are white in one, and a bit dark purple in the other.

If i leave these to dry out, will the seeds turn black, or should i have left them on the plant?

Cheers

I would just leave them on the plant, it does look a bit messy but the birds manage to get them out of the flower head on their own.