What's a monotype? It's famously called "the painterly print," and it is a kind of hybrid of painting, drawing, and printmaking. It is a one of a kind print; it is not made in series (although, after pulling one print, you can often get a lighter, "ghost" image if you pull a second one, and that can have merit on its own, or it can be used as the basis of further exploration by drawing on top of it). Degas, that inveterate experimenter, is probably the most cited of the modern masters of the technique, and other more recent practitioners include Richard Diebenkorn , Michael Mazur, and Eric Fischl.
Monotypes are one of a kind because there is no permanent mark made in the plate; no cutting, or biting, or relief. You use ink or paint on a smooth, non porous surface, and the ink sitting on the plate is transferred to the paper when you run it through a press. There is nothing permanent to the image, although, again, you can use the ghost image on the plate to work in series, adding to what has been left behind. When you want to make a new image, you wipe it clean and start again. I use a zinc etching plate. It's a fun, simple, personal, and infinitely expressive method. It can be addictive. I learned it way back as an undergrad, from a teacher and artist named Katherine Kadish.
In 2003, I bought a small press for my studio and since then every couple years or so I work in monotype. I find it helps explore new and old themes and encourages new ways of thinking about technique. It loosens me up. I've usually used oil based intaglio ink, or even just oil paint, to make monotypes, but most recently I've been exploring Akua's waterbased inks. I like them. They've allowed me to work with my cool blue "TV" palette, and to work the image up in ever more painterly ways. They also eliminate the step of dampening the paper, and of course they make clean up easier and safer. I'm looking forward to working with them even more. In the mean time, I'll continue to post some recent examples. I'm trying out Etsy by offering some monotypes there, hoping to make a a little extra money to help pay for the studio in tough times.
Degas' famous description of monotype was something along the lines of (and I'm working off the top of my head here because I'm feeling too lazy to google it) "a drawing made in greasy ink and run through a press."