To Air Is Human

I like to do a lot of paintings and illustrations on black. And as a result, it has become common practice for me to use black papers, showcards and bristol board. (I also find these substrates to be ideal for mail order artwork...in other words, its easy to roll them up into tubes or long boxes, for shipping).
However I am getting a little tired of the "same-old" thing, and I 'm thinking of going back to an earlier practice of painting on gessoed masonite and canvasses. (Did I spell that right?) Canvas is good for being able to roll up the painting and transport it, but its not a smooth surface - and if you want smooth, you have to make your own gessoed surface.
To do this, you need a piece of masonite (or "hardboard", purchased at the local lumber store). I like to buy a 4' x 8' sheet and cut it down to as many pieces as I wanted. Quite often four 2' x 4' sections. Some fine-med wood sandpaper, maybe 240-320 grit? to create a "tooth"on the smooth surface of the masonite...and then start applying layers of gesso. Tubs of gesso ("canvas ground") are available at your local art supply store.
I paint (usually brushed, not rolled) a good heavy coat of gesso on the board, and once it is dry, use an electric orbital or palm sander to smooth the layer. Coarse paper is required at first to cut down the heavy gesso (it sands just like wall plaster), so wear a dust mask. Then I start adding more layers and sanding smooth each layer (reducing the sandpaper grit) until I have applied and sanded enough layers to achieve an almost glass like smooth surface. (The smoother the better!) Sometimes more than ten layers!

Its an absolutely wonderful surface to paint on! The gesso is quite forgiving with its absorbency, and yet the smooth glass-like surface is technically challenging but so accurate, allowing you to produce the crispest of lines and details.