side margins become inner and outer margins. Whether they are in a single page or part of a two-page spread, outer margins become the proverbial thumb space. Margins need not be the same size on all four sides. For example, you could have a 2-inch top margin and 1-inch inner, outer and bottom margins. But if your layout has multiple pages or screens, maintaining a consistent margin setup across all your pages adds visual unity.
Top margin, also called head space
Right and left margins or “thumb space”
Establishing format gridlines and margins is the essential first step in creating your layout. But there are other types of gridlines you may need to add to your design sketches, such as bleed, live area/ safety area and trim size.
Trim size. In commercial printing, trim size refers to the physical dimensions of the flat page. In many cases trim size corresponds directly with format size. The trim size of a traditional U.S. letter is 8 × 11 inches, for example. However, consider a more complex piece such as a pocket folder. While the finished size of a pocket folder is typically 9 × 12 inches, a pocket folder at the printing stage is much larger. The width doubles, and the height increases by the size of the pocket. When designing complex print pieces, you need to add gridlines to indicate trim lines and folds. Without them, you might find yourself with backwards brochure panels and upside-down pockets. You might expect that you have every square inch or pixel of your trim size or screen to fill with your design elements. You’re right—and wrong.
Bottom margin, also called foot space or footer
Above: A single page with margins. Below: A bleed line (pink) usually sits 18 inch beyond the trim line (black). To prevent unintended cropping, keep content inside the live area (yellow).
Bleed. Running page content right to the page’s edge is called a bleed. The effect is to bleed material—background color, visuals, type—right off the layout. Bleed lines and trim lines go hand in hand. To create a layout with a bleed, a designer makes the bleed content extend just beyond the trim size. Commercial printers take the slightly extended design, print it to a larger sheet of paper and trim the edges to achieve the desired finished size. This is where the term trim size comes from, by the way. Establishing bleed lines as part of your grid helps you ensure that your printer can properly trim your printed piece.
Bleed line
Trim line
Live area
Print content may bleed or not, depending on the designer’s preference. Screen content, however, always bleeds. Even when the content of Web pages, video or commercials stops shy of the viewing device boundaries, something—typically a solid color—fills the rest of the screen. Make a point of choosing
Chapter 6: What Is a Grid?
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