My hands-down favorite medium would have to be graphite or lead, the core of a pencil, the material that makes the marks on paper. Lead makes the words, images, idle thoughts (doodles), specific information — crucial and otherwise — visible.
With the lead from a pencil I can make thin delicate words and lines, bold solid black forms, and wispy, smooth gray shadings. All with the same soft lead. Everybody can, anybody — no experience necessary. Everybody can do it, from the very beginning, right out of the box.
Any pencil will do, but my absolute favorite would have to be a TICONDEROGA #2, brand new (they don’t last long) and freshly sharpened. Golden yellow (Cadmium yellow), six-sided, with yellow and green ferrule, and at one end a pink eraser.
Sharpening a new pencil, cutting away the wood to get at the lead, was, at first, very conservative: a hand-held sharpener with one or more hobs for various thickness of pencil. A little later on, and more interesting and bold: a penknife (a non-threatening, pencil-sharpening-only penknife). More limiting: a wall- or desk-mounted hand-turned apparatus.
Up/down, side/side, cross/cross, scribble/scribble, swirl, and then smudge/smudge with a thumb or finger. A wonderful way to make marks on paper. Spare use of the eraser preserves it and avoids losing some potentially useful bit.
Number two is a degree of lead soft enough for most of my needs, but if I must have a very bold, extra-black image for a dog or a train in a tunnel or the night sky, only an EBONY VERIBLACK will do. The whole pencil is black, the lead very soft with unparalleled smudge-ability.
Sketching, note-taking, list-making using a lead pencil in sketchbooks, on envelopes, and on bits of paper of every size and description is a necessary, useful, and pleasurable part of my life. Finding a bit of an old pencil note or sketch, no matter how cryptic, can bring entire events into focus.
Never-used lead pencils also have their place. I often come across pencils in my drawer that say Grand Rapids, Michigan; Bismark, North Dakota; Meteor Crater, Arizona; Mississippi State University. I’m sure the lead in any of these pencils would produce very satisfactory images, but I can’t bring myself to spoil the typography in order to use them. So I’ll just sharpen another TICONDEROGA #2 and get busy.