The grid in design is a series of intersecting horizontal and vertical axes used to structure content throughout a document. Grids can be either loose and organic or rigorous and mechanical, as long as they provide a framework for the document that makes consistent use of alignment and repetition possible. Grids don’t dictate the design, but rather they support the intentions of the designer. The grid is made up of several different elements including margins, bleeds, columns and rows.
Columns & Rows
Columns are vertical divisions of space and rows are horizontal divisions of space. Columns are usually blocks of vertical space (as show in the illustration) separated by gutters that allow text to be place next to one another without touching and become jumbled. Columns also allow for large blocks of text to be set at an optimal width for reading, called line length. If a column is too wide it becomes difficult for your eye to track from the end of a line and back to the next line. When column widths are set at an optimal size there is no strain and the text is easier to read. The size of an optimal line length varies, but generally should be somewhere between 4 and 6 inches. If it becomes larger or smaller the text becomes more difficult to read.
Rows are sometimes called flowlines because they often play a supporting role as points of alignment rather than blocks of horizontal space. In the illustration above you will notice that the columns are separated by gutter space while the flowlines are simply linear indications are not separated by gutter space.
Together columns and rows form the basic structure of the page. The guides they provide aren’t visible in the final product, but the framework should be evident. The example below shows two pages from a multi-page document. I’ve drawn in the grid lines that were used to lay out the elements on the pages. You can see that from page to page there are similar placement of different items using the grid lines as points of alignment.
Thought the content is different on each page the layout appears consistent because the same grid was used.
The example below shows how a literal grid was used in the design. It is very evident where the columns and rows are used. Though not all design may have such an evident grid, it would be difficult find a design that is without a grid.
Margins define the active area of the compositional space and direct the viewer toward the visual elements. Margins can vary in size depending on the format of the page, as well as the textual and visual content of the design. Left and right, as well as top and bottom, margins can be equal all around or larger and smaller, depending on the proportions of the page. On double-page spreads, the inside margins must be large enough so that nothing is lost in the gutter. In addition, the margin space can be used for the placement of subordinate elements, including folios and footers.
Smaller margins increase the usable surface area of the composition, which accommodates complex designs with various visual elements. Larger margins decrease the active space of the page but increase the amount of white space, creating an open visual environment that is approachable, inviting, and soothing. For example, books of continuous text without extensive visuals benefit from large margins. Ample margins provide a stable compositional space that directs the viewer toward the positive areas of the design, while also leaving finger room to hold the piece.
Margins are not intended to trap the visual elements within the compositional space; they are used to activate the positive areas of the design. In many cases, the outer margins can be broken to allow the visual elements to move off the page. The implied movement expands the visual environment outside of the composition.
Most printers can’t print completely to the edge of a piece of paper. When you want your document to have images that extend to the very edge of a page you need to design with a bleed. A bleed is just a small extension of the page, usually .125 inches, that adjust the document to be printed at a slightly larger size and then trimmed to the correct size. The trimming ensures that the graphics extend to each edge.