From childhood on I have expressed myself through art, but kept that side as a hobby and choose science for my formal education and professional career. This, supposedly incompatible combination, made me a better and creative scientist and a more detail oriented artist.
I often take mental snapshots of striking subjects and events and then spend considerable time mentally photoshopping a composition, details and colors into a mind painting, long before I put the first stroke on paper.
My favorite medium is soft pastels. They can give stunning effects and results, not at all the insipid colors and textures, most people associated with these "chalks".
I am constantly trying to loosen up and suggest detail in my work, rather than actually paint it. However, I keep returning to a painting, when it's supposed to be finished. Oh well, that is probably the scientist in me and the charm of my work.