Sketching and journaling I feel is the backbone of my Plein air practice.
I believe that it really hones one's seeing skills - besides it's a wonderful recording of life.

“In every case I worked directly from the living model, sketching rapidly as the animal moved in front of me.
Working in this way is by far no means easy. It is often extremely frustrating; but there is something infinitely more sensitive and beautiful in the imperfect line drawn in a frustrated attempt to capture the living, breathing, moving subject; than the contrived line done in an air-conditioned studio in response to a photograph.”
​Dylan Lewis (sculptor)

Little sketch books. Easy to carry anywhere.

I use tiny sketchbooks to carry on my hikes.
On my return I paint my sketches having commited the colours to memory.