Macarons - can you tell me why they're bumpy and lined? Pic here

[ygritte2]

First time making macarons with DC and we followed the recipe to the letter.Using a piping nozzle (which was sort of serated) one batch worked, one didn't.
Also they have a bumpy finish even though we put put the almonds in the food process or and sieved everything.
I'm going to make them for parent's Golden Wedding next week so would like them to be better.
Any help appreciated.

Did you tap the tray once they'd been piped? I've never made them them but got a vague memory of them doing it on Bake Off. Something to do with air bubbles?

They look pretty good for a first attempt!

Did you leave them in a warm place for a while before putting in the oven? Once they've formed a 'skin' you can basically prod the tops and smooth out any irregularities or bumps (I usually have to remove the 'nipples' that result from my poor piping).