It has come to my attention that not everyone in the universe knows how to operate a flatbed cylinder proofing press. This is both a shocking development and an opportunity to flex my blog muscles. What follows is a simple explanation of the letterpress process.
A flatbed cylinder (letter)press like the one I use is basically composed of four things: (1) The feedboard, where you get your paper ready to feed it into the press, (2) the bed, where your type, linoleum cut, printing plate or other inked surface lies waiting, (3) the rollers, which distribute the ink evenly and put ink on your type/lino cut/plate, and (4) the cylinder, which generally turns with a crank, rolls over the type/lino cut/plate, and presses your paper against the inked surface.
I have expertly labeled these four things on the lovely, factory-fresh press above (a Vandercook SP-20, the kind of press I own in the States which currently lives at The Cracker Factory in Geneva, New York) and on the slightly more broken-in press below (a FAG SP-40, the kind of press I used today at Ink Spot Press here in Brighton.)
You can see two kinds of roller here, metal rollers that distribute the ink evenly, and rubber rollers that smush ink onto your type or plate. There are two of these rubber rollers, but only one is visible below. This press is already inked with a translucent gray ink that is difficult to see, even though it is coating all of the rollers. If the press were inked with black ink, all of the rollers would appear black.
Everything in the bed of the press is designed to be a certain height so that the ink evenly coats all of the surfaces that are supposed to print. This height is related to the historical height of metal type (.918 inches) and so is referred to as “type high.” Today I am printing from a plate that is stuck to a metal base, but you can see below (thanks to a handy piece of type) that the combination of the metal base plus the little plate stuck on top is type high.You can print from all kinds of things as long as you bring them up to this specific height. Anything lower will not get a coating of ink, anything higher can damage the rubber rollers.
With those basics in mind, watch this: I take a clean piece of paper and slide it under the grippers on the cylinder where it waits just under the feedboard. These grippers are operated by a foot pedal. When I release that pedal they clamp down and hold the paper in place. I am careful to align the paper with a side guide.
Using the big crank on the side of the cylinder, I begin to move the cylinder forward. The paper is carried along by the grippers, curving over the cylinder towards the plate that waits below in the bed.
The paper continues to curve around the cylinder as the cylinder and all of the inking rollers move forward toward the far edge of the bed. The rubber rollers roll over the plate and give it a fresh coating of gray ink.
The paper, still held by the grippers, is smashed against the plate as the cylinder rolls over it. The ink is transferred to the paper and the paper is given that ‘bite’ or impression that is associated with letterpress printing as it is forced with high pressure against the plate. The amount of this impression, the depth of the bite, is determined by how much paper is wrapped around the cylinder. The more paper (called ‘packing’) there is around the cylinder, the higher the pressure against the plate and the more intense that bite into the printed sheet.
And there you have it. One page at a time, one color at a time. While there are many different makes and models of presses, the principles of letterpress remain the same.