Thanks for these inspiring comments, guys. As expected the 140 gsm paper in the sketchbooks I use does cockle easily, though. So I'm in a bit of a dillema with what to use If I want to paint in the field. I go through sketchbooks very quickly - one a month sometimes - so only use ones at a fiver a time. I don't really fancy spending loads on expensive paper. I've got a 200gsm pad to try this weekend. One thought is to carry two: my standard WHSmith's polypro A4 and something suited to watercolour. I tend to go cheap because of the amount I use, but I find it's the only way I can get 'into' the bird.