Helpful Tips - Prepress
Bar Code: Identifies a book’s ISBN, title and price in scannable format. We can digitally generate barcodes for you. We also accept them on film, positive prints, or digital files. Barcode Tips.
Bleeds: Printing that extends to the edge of the page after trimming is called a bleed. To ensure ink coverage to the bleed edge, we need ¼ inch of inked paper to trim away after printing.
Color Separation: To reproduce a full-color photograph, we must convert it into the four primary colors used in process color printing—cyan, magenta, yellow, and black (CMYK). Using a professional scanner, we scan the photograph and convert it to CMYK. The image can now be imported into a page makeup program and placed in a book cover layout. To print the image, we create four separate press plates—one for each of the four colors.
Dots Per Inch (dpi): DPI measures image resolution which is composed of dots. The more dots per inch, the greater the clarity of the image. DPI measurements can be adjusted on monitors, scanners, printers, and image setters.
Flight Check: A computer program that reads a disk and identifies missing fonts, embedded graphics, bad traps, and over 100 other potential problems. Our preflight department regularly uses Flight Check to quickly identify these issues at the onset of printing projects.
Fonts: A font is a set of characters in a particular typeface. Font Tips.
Halftones: Most printing presses, including ours, cannot print continuous tones. To effectively print photographs and drawings, we must first convert them to halftones. A halftone is an image photographed through a screen so that the details of the image are reproduced as a series of small dots, which simulate the appearance of continuous tones. The screen pattern and frequency of dots, measured in “lines per inch,” will determine the quality of a reproduction. For halftone instructions, see Camera Ready Copy and Digital Submissions.
Image setter: Equipped with a powerful laser, we use this high-resolution device to output digital files onto film.
Knockout: The best way to print type or line art over a photograph or other variably color background, is to “reverse” or knock out the type/line art from the background and then fill in the knock-out with your desired color.
Margin: Unprinted space on a page surrounding a block of text. Margins are left to the customer’s discretion, so long as there is a minimum ¼ inch margin. If your book requires perforation or 3-hole drilling, check with your Customer Service Representative for appropriate specifications. Margin Tips.
Pantone Matching System (PMS): Pantone is the brand name of ink colors, and the Pantone Matching System is widely used in the printing industry to identify colors. Color Printing Tips
PDF’s (Portable Document Format): PDF is a universal file format that preserves all the fonts, formatting, and graphics of a document, regardless of the application and platform used to create it. PDF files are compact and can be shared, viewed, and navigated by anyone with free Adobe Acrobat Reader software.
In our experience, the most reliable PDF’s for printing purposes are PostScript files distilled through Adobe Distiller. If you do not have the Distiller® software, we can work with your PostScript® files with equal success.
PostScript®: Developed by Adobe, this standard page description language is supported by both MAC and PC-compatible platforms. It is a device-independent format, which allows the same PostScript file to be output on different printing devices, including laser printers and our imagesetters. If your material is in a program that we do not accept, we will ask you to convert your files to PostScript code, so that we may output them through our imaging systems. PostScript Instructions for Word and other Windows applications.
Resolution: The sharpness or clarity of a digital image, measured in dots per inch (dpi). The higher the dpi, the better the image detail. Most laser printers have a resolution of 300 dpi. Imagesetters used by professional printer offer resolutions ranging from 1,000 to 3,600 dpi.
Spine Width: To determine a book’s spine size, divide the total number of pages by the paper’s thickness, measured in “pages per inch” (PPI). Click here for spine sizes matching our paper.
Trapping: An overlapping area where two different colors of ink meet, used to compensate for misregister, thus preventing an unwanted white edge between colors.
