On a walk with sketchbook and pens you can get a lot of drawing done that may also be useful for artwork development, (plus it gives you a reason to stand still and look without other people thinking you are a bit odd). If I have a focus and an idea of what I might see, this is a walk of attention and observation, trying to get the most from being somewhere at a particular time and not missing the moment.
Rose hips ripening no.2 is an ink painting developed from sketches made using brush pens and chunky felt tip pens. For any painting I want it to be as light resistant as possible, but in my sketch books this is not an important factor.