Top Ten Manual-No. 7 File Format

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. 

EPS (Encapsulated PostScript)
EPS is a format that encapsulates or wraps all artwork (vector and bitmapped) in PostScript code; it includes a low-resolution preview of the artwork for display purposes. This format was designed to create files that could be placed in page layout applications, then left alone. EPS files are to be printed to a PostScript printer or RIP (Raster Image Processor). You can expect poor-quality EPS image output from low-cost inkjet printers.

When you place an EPS file in an application, it’s protected from any major changes to its structure: You’re able to scale the artwork, but you cannot down-sample the resolution, change the type or colors in the art, or even crop correctly. To make these changes, you’ll need to return to the originating application (such as Photoshop or Illustrator). Or you can save the file as a TIFF instead.

The low-res preview displays the artwork onscreen; it’s used when printing to a non-PostScript printer. You can choose between several previews, from a very coarse 1-bit (black-and-white) preview to an 8-bit TIFF preview. Using Photoshop on a Mac, you can choose a JPEG preview, which creates a richcolored, smooth preview and a smaller file size, too.

The EPS format offers lossy compression in applications like Photoshop, which can result in small file sizes. If you use spot colors, you can choose a special flavor of EPS called the DCS (Desktop Color Separation) format. Available in Photoshop, it saves a file containing spot colors for accurate printing from layout applications such as InDesign and QuarkXPress. The EPS format also allows you to save special halftone screens, useful for printing duotone files. See Tip #2.

PDF (Portable Document Format)
The PDF is useful for saving artwork featuring precise layout and a significant amount of formatted text. Over the years, PDF has grown in stature from its humble origins as a “precise file exchange” format to a mainstay in the fields of prepress and electronic learning. One benefit: PDF allows you to embed fonts in a document, so type and layout both preview and print consistently wherever the file travels.

PDF files are generally small in size, because of the JPEG (lossy) compression. This makes them ideal for e-mailing and web publishing. PDF supports embedded ICC profiles and can display colors in the document in a consistent fashion even at a remote site on a calibrated, profiled monitor. This makes it ideal for sending proofs to clients. See Tip #3 on how to make PDF proofs that will dazzle your clients!

PDF documents will save layers in your artwork, making it easy to return to applications such as Photoshop and Illustrator to edit the artwork. The neat thing about this is that the JPEG compression degrades the PDF, but not the layered art—so you can resave as PDF with JPEG compression, with little loss to image quality. Some security measures such as password protection and disabled printing can be built into a PDF file, making it a good choice for saving portfolio and client review art.