Part of our series where we seek to uncover unfamiliar terms in the world of print.
After everything has been carefully designed and proofed in the prepress process, it’s time to send that project to the printing presses.
At Dual Print & Mail, we use offset, digital, and web presses. Each press has its own capabilities and serves different functions:
- Offset presses run at rapid print times and achieve high volumes of production. Ink is rolled onto a plate, and then transferred onto and absorbed into paper. Offset presses are best suited for projects that require long runs of the same static image.
- Web presses (not to be confused with web-to-print) also allow for rapid production. Web presses are run on continuous rolls of paper (as opposed to cut sheets), and can print on both sides of the paper at once.
- Digital presses are perfect for short runs of highly variable pieces. Instead of rolling ink onto a plate and transferring it onto paper, toner is electrostatically charged and then transferred to the paper.
Whether you use an offset, digital, or web press (or any combination of the three) let’s take a couple minutes to break everything down and define some terms you are going to run into when it comes to printing presses.
Printing Press Terms to Know
- Bleed: Once trimmed, printed images that extend to the edge of a sheet or page are known as bleeds.
- Bulk: How thick a piece of paper is. Bulk can be measured in thousandths of an inch, or number of pages per inch.
- Coated Paper: Paper whose surface, prior to printing, has been applied with a coating that produces a glossy or silky finish.
- Collating: Taking signatures and pages and aligning them in proper page order.
- Color Bar: Strips of color that are printed along the edge of a printed piece, used to determine color consistencies across press sheets, so each sheet being printed exactly matches the next.
- Continuous Rolls: Large rolls of paper used in web presses that are fed through the printer as one continuous sheet, cut after they are printed.
- Cut Sheets: Paper fed through the printing press as single sheets of paper, already cut before they are printed.
- Densitometer: An instrument that is used to measure the density of ink (compared across color bars) to make sure that each sheet is color consistent.
- Density: The precise make-up of an image, including weight, tone, and color.
- Ghosting: Faint images that appear where they are not supposed to, often as a result of printing dense images.
- Grade: The quality level of a piece of paper, determined by brightness, weight, and finish.
- Grammage: A term for the basic weight of a piece of paper.
- Hickey: Marks that appear because there was dust or dirt on the sheet of paper that was printed, causing an irregularity in ink coverage.
- Ink Drawdown: Used to evaluate ink colors and determine color consistency, these are samples of ink and paper.
- Ink Holdout: Ink normally absorbs/soaks into a piece of paper, but coated papers are more resistant to that. Ink holdout doesn’t allow for penetration of ink.
- Ink: Liquids used in inkjet printers. Absorbs into a piece of paper.
- Newsprint: Thin, inexpensive paper made from wood pulp.
- Overrun (overs): Occurs when more copies are printed than originally specified. Also referred to as run-on.
- Pantone Matching System (PMS): System of color swatches that shows availability of color options. Colors are standardized by Pantone to ensure color consistency across all projects.
- Picking: When ink is too tacky (sticky) for the paper it’s printed on, removing its coating and ruining the surface of the paper.
- Press Sheets: Standard pieces of paper that are used in printing presses.
- Toner: Fine powder used in digital printers that sits on top of a piece of paper and doesn’t fully absorb into it.
Top Takeaways on Printing Presses
- Depending on output quantity, projects can be printed on offset, digital, or web presses.
- Ink is used on offset presses, and toner is used on digital presses.
- Paper can either come coated, or be coated later on in the finishing process (we’ll explain more about that in a later post).
What has been your experience with printing presses? Are there any other terms you’ve come across that you’d like to share with us, or ask for clarification on? Comment below!