What is design for print? File types

We routinely use various file formats for saving, opening, and printing files. But questions persist in many minds about whether the file formats they’ve chosen are in fact appropriate for their print workflow. Are the specific options they selected when saving their files the right ones? Are there other choices that improve the quality of their artwork or output?

Raster and vector Raster art, also called bitmapped art, is comprised of a grid of colored pixels that make up the image. Scanners, digital cameras, screen capture applications, and paint programs generate and save raster art. Vector art is comprised of mathematically defined objects with specific shape parameters like arcs, circles, and squares. CAD (Computer-Aided Design) programs and drawing and illustration packages produce this kind of art.

Tip #1 In Photoshop you can save a copy of the file in its present state while continuing to work on the original file. To do this, check the Save: As a Copy option in the Save As dialog. This is similar to photocopying a document and filing it away for future use, while continuing to work on the original.

I might as well say this upfront: The main file formats used for print work actually do not alter or improve the image data and appearance in any way. They merely control how the file is written to disk. But how a file is written will affect how the file is handled by the application that opens it. A key question: Is the application merely to open the art and print it, or will you be editing, cropping, scaling, and manipulating the art as well? Why different file formats? Most file formats are made to handle a specific kind of artwork, typically either vector or raster art. Luckily, in the print world, recommended file formats handle both kinds of artwork very well. So how do you know which format to use, and when?

It gets a bit confusing when we realize that mainstay applications such as Photoshop, Illustrator, InDesign, and QuarkXPress can use raster as well as vector art. So to exchange files between these applications, you should use “standard” formats that can contain any kind of artwork for saving and opening across applications and platforms.  The main players in this category are the TIFF, EPS, and PDF formats. Each uses the exact same image data but writes the file with specific permissions and limitations for editing and manipulating the file content in applications.

When to use what format?
Although you might create and archive artwork in its originating application in its “native” format such as PSD, AI, etc., you might also want to save a copy of the file to send to a client or offsite for output. The Save As option in the File menu allows you to save a copy of the file in one of the standard formats. Save As also allows you to rename the file, flatten layers, simplify artwork, reduce the file size, and remove any extras such as annotations, paths, etc. See Tip #1.

Learning standard formats
Each of the standard formats was designed to fulfill a certain need and has unique advantages in certain conditions and workflows.

TIFF (Tagged Image File Format) TIFF is an industry standard designed for the handling of raster or bitmapped images. It can save black-and-white (1-bit), grayscale, index color (256 color), RGB, LAB, and CMYK images. It supports 8 bits/channel and 16 bits/channel files, and various forms of compression. Saving in TIFF means that you can save or embed an ICC color space profile in the file, making it the format of choice in a colormanaged workflow. In other words, just about any application that can read bitmapped art will open TIFF files. The attractive aspect of TIFF files is that once placed in a program, you can edit, scale, and manipulate all aspects of the artwork!

A CMYK TIFF file will often print faster than another format because of the way the image data is sent to the printer. TIFFs offer a variety of file compression options, including the excellent “lossless” (nondegrading to image quality) LZW compression. Photoshop users can also compress files using lossless ZIP compression, and for higher compression rates and more compact file sizes they can choose “lossy” (degrading to image quality) JPEG compression.  In Photoshop CS, the TIFF format will save layers, adjustment layers, and spot colors, though at present these files can be read by very few applications. If you encounter a problem opening a Photoshop TIFF file in a layout program, you’ll need to reopen the file in Photoshop. Choose Save As from the File Menu, check Save: As a Copy, then uncheck any checked boxes pertaining to Alpha Channels, Layers, Annotations, and Spot Colors. Choose TIFF and click Save.