Thanks for your help, but I’m afraid that doesn’t solve my problem.
I need the write-on effect to reveal the straws of the reed as if they were growing. With Write on Transparent set on the first write-on effect, it shows nothing and the rest just paints on the image instead of revealing it.
I solved it by making one layer for each straw. That means I have put the image on 30 layers, each one with another path for a single straw. On every layer I set the write-on effect to reveal original.
This is rather complex, but the result looks fine. I was just hoping to find a more “elegant” way instead of building up 30 layers with the same image.
Well, one problem remains now: How do I get rid of the dots at the beginning of each mask-path? :-/