Sketchbooks are a perfect way to collect ideas and they're a real pleasure for me. I have different sketchbooks, big and small. They are filled with lots of ideas: trials with coloured pencil or ballpoint, sketches of my garden plants, a beetle I found in the street, lots of combinations of lettering and illustrations, drawn or written, everything that comes into my mind. They're a source of inspiration for my bigger free work.
A sketchbook allows me to create pictures surreptitiously without inhibition, a place where it's safe to make mistakes. So, unlike my concertina books, my sketchbooks aren't made for their own sake, although some pages could very well be framed. For the last few years I've also had a travelling sketchbook that I only use during my trips and travels or when I am teaching abroad.