Print advertising and publication dimensions are important for preparing and formatting an illustration for delivery to a client or printer. Nearly all periodicals and many independent publications rely on a system using three measurements or guidelines for the preparation of artwork. These guidelines are called the “trim”, “bleed”, and “live area” dimensions.
|© 2013 Don Arday.|
Somewhat self-explanatory, trim is the term that is used to describe the absolute horizontal and vertical area dimensions of a publication. Most publications are printed on paper that is larger than the page dimensions to allow for processing and handling as well as image demands. In the finishing process, guillotine knives trim the printed sheets to their proper final size.
Every print publication has trim dimensions. The final compositional appearance of an illustration, whether it will bleed or not, should be based on the proportion of the trim dimension.
When imagery or design elements are produced with the intention of extending beyond any edge of a page of a publication this known as a bleed. In other words bleed is used when it is it is necessary for the image or a portion of it to extend beyond the trim edges. Bleed area dimensions are provided by publishers to ensure the image will be placed on a page for proper reproduction, and to provide a margin of safety for variations of movement as the paper passes through a printing press.
Not all publications use bleeds. If a publication does not permit bleeds then there is no need to prepare artwork with a bleed dimension. Newspapers would be one example of this. The normal allowance for bleed is 1/8" beyond all sides, although on posters and large publications it can be wider.
With the extreme accuracy of today’s printing presses, there is some debate as to whether live area in a publication is still necessary. The live area is an area within a page that is designated a safe area for all content. In print ads, the live area it typically 3/8” inside the trim, or in some cases it can be as wide as 1/2”. Imagery and content meant to bleed will extend beyond both the live area and the trim.
In other forms of print publications, such as magazines, the live area is actually a margin established for layout purposes. In magazines for instance, the edges of the live area would indicate the furthest extent that text could occur at the top, sides, and bottom of all pages. The publication designer establishes a live area margin in the initial layout stages of a new publication design.
The slug area is every part of a press sheet that will be cut off of the final print. This includes any bleeding image content; all crop, fold, and registration marks; and any color bars.
Crop marks indicate where the page is to be trimmed. They are short, thin, solid, horizontal and vertical lines, placed outside of the trim area at each corner of a page that provide a cutting guide for the finishing process. Crop marks are provided by who ever prepares the document for print, be it an, illustrator, art director, designer, or production artist.
Fold marks indicate where the paper is to be folded if needed. These marks are short dash or dotted horizontal or vertical lines, placed outside of the trim area along the edge of a page to indicate where a desired fold is to occur. Fold marks are provided by who ever will prepare the document for print.
Center marks are included to indicate the horizontal and vertical center of the printed page. These marks are used in the post-printing process to help align pages to finishing machines, etc.
A printer uses registration marks to align the separate colors of ink when printing a page with more than one color, Since each color of ink used in printing is applied with a separate set of rollers to a separate printing plate, registration marks are crucial for accurate alignment. There are many different kinds of registration marks used by printers, each with its own purpose to aid in printing a variety of different types of imagery.
Color bars are placed beyond the bleed area to allow the printer to control the color on the printed page. Color bars not only provide a constant stable standard for measuring the flow of various colors used in a printed image over the duration of a print run, they measure the visual properties of ink as well as the performance properties of the printing press. They also provide information for comparing a color proof to the printed version of an image.