I don't remember what the seeds that I planted this spring looked like. Are the seeds white colored - or does that mean that they aren't done yet?
Take a peak at the site below; 2nd row, last picture. Hope it helps.
Here is a link that might be useful: seed pic
If they are white, something isn't right. Maybe not ripe, or maybe you have the wrong thing. I just waited until the flowers were dried out and shook them into my hand--tiny black seeds fell into my hand very easily.
Sorry Hollywog, but I think you are mistaken. Love Lies Bleeding seed are certainly not black. They are a rose, pink or lightly tinted white color. Just like the picture peat moss linked.
There are other kinds of amaranthus that have black seed but the love lies bleeding are a rosy reddish color.