In most cases, the printer feeds paper into one end of an offset press and collects sheets at the other end of the press. At this point, these sheets have usually been printed on only one side. The printer then sets these sheets aside to dry. Once they are dry, he can turn the stack of sheets over and then feed them back into the press one by one to print the other side. This is called “backing up” the sheet.
Not every press prints only one side at a time, though. Presses that print both sides of a press sheet at the same time are referred to as “perfecting presses.”
A “blanket-to-blanket press” is a kind of perfecting press. It is set up so one blanket prints one side of the sheet while the other, corresponding blanket prints the other side of the sheet. Moreover, as this happens, each blanket acts as an impression cylinder for the other blanket. That is, the upper unit—above the press sheet—includes ink and water rollers, as well as a plate cylinder that deposits ink on the blanket cylinder immediately below (yet still above the paper). This blanket presses down against the sheet and deposits ink. Pressing upwards against the press sheet with equal force from below is the other blanket cylinder. Below this blanket is the plate cylinder (as well as the corresponding ink and water rollers) responsible for inking the bottom of the press sheet. Ink laid down on the lower plate prints on the blanket above, and then offsets to the paper above that.
If this is confusing, picture an antique washing machine with drying rollers. You feed the wet piece of clothing between the rollers and then crank it through. The two rollers on the antique washing machine correspond to the blanket cylinders. Then picture two plate cylinders (one above the top washing-machine roller and one below the bottom washing-machine roller). With these extras, you now have four rollers: two for plates and two for blankets. And the press sheet gets pulled between the sets of rollers—just like a wet piece of clothing gets pulled through the wringer.
Why should you care about this complex roller scheme? Because it saves money and time. If your printer has a blanket-to-blanket press, or any other kind of perfecting press, he can print both sides of the sheet at once and therefore significantly shorten the time needed for printing.
Leave it to the printing industry to come up with colorful jargon.
Kiss-cutting refers to a specific type of die-cut labels. Let’s say you are producing a sheet of rectangular self-adhesive labels that will be hand-peeled off a backing sheet of glossy paper. To make the process easier, you want to have the die-cutting press cut through the label paper (so you’ll be able to easily remove it from the backing sheet). However, you don’t want the die-cutting blades to chop all the way through the backing sheet. If done correctly, this makes peeling off the labels much easier. This process of die-cutting just through the label paper but not through the backing sheet is called “kiss-cutting.”
While we’re discussing labels, here’s a closely related term. On a roll of “butt-cut” labels (laid out on the roll of backing paper with one label above another like a ladder of rectangles), the bottom of one label touches the top of the next label on the roll. With no gap between the labels, there is no wasted space (which would add up to a savings on a large roll of labels). Usually, these labels also extend to the edge of the backing sheet (the left and right sides). That is, there’s no margin on any of the four sides of the labels. A benefit of regular die-cut labels (with space between the labels) is that the corners of the labels can be rounded. On butt-cut labels, the corners are square, and the labels are therefore a bit harder to peel off.
HEAD, FOOT, AND FACE OF A SHEET
A press sheet is cut and bound into a book as a single leaf (front and back of a page). Whether the book is saddle-stitched, perfect-bound, or case-bound, there are a number of printers’ terms to help you identify the various parts of the page.
The part of the sheet you grasp when you turn a page—the vertical, outside margin—is called the “face” of the sheet. The top horizontal part of the page is called the “head,” and the bottom horizontal side is called the “foot.” The fourth side of the page is the “bind edge,” which is attached to the spine of a perfect-bound book (or the stitches of a saddle-stitched book).
You may find it useful to know these terms. If you are producing a magazine (a magazine is a book), and you want to bind in a reply card, your printer will ask whether the card should “float” (be attached somewhere in the middle of the open page spread) or whether it should “jog” to the head or the foot. Once you know that “jog” means that the bind-in card will be “aligned” with the head or foot, your knowledge of the anatomy of the page will be most useful in communicating your decision.
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]