File Formats for InDesign
When discussing file formats for use with InDesign, we need to consider three aspects of the program: What formats can be opened by InDesign? What types of files can be placed into an InDesign document? What file formats can be generated (output) by InDesign?
Opening Documents and Templates in InDesign
InDesign, naturally, opens its own documents and templates. InDesign documents use the file extension .indd, templates use the extension .indt, and InDesign books have the file extension .indb.
The Open a File dialog box, shown in Figure 3.48, offers the option of Open Normal, Open Original, or Open Copy. Generally speaking, Open Normal is the appropriate choice. Open Original is used to edit a template, and Open Copy automatically creates a duplicate of the selected file, leaving the original unchanged. (To create a new document from a template, use Open Normal.)
Figure 3.48 The Show pop-up menu offers the choice of All Readable Documents or All Documents.
In addition to InDesign's own documents and templates, you can open documents and templates from PageMaker (version 6.5 or later) and QuarkXPress (version 3.3 or later). Note that InDesign does not support Quark XTensions. Any graphic added with an XTension won't display or print properly.
To make sure that linked files in a PageMaker or Quark document are available when the file is opened in InDesign, copy them to the save folder as the page layout document.
InDesign also uses the Open command to open Object Libraries. Object Libraries are collections of graphic elements, pages, text, guides and grids, and shapes. When opened, these elements appear in a palette, ready to be added to the open document. InDesign library files use the file extension .indl.
Placing Files into InDesign Documents
Although it certainly is possible to copy/paste or drag/drop to add graphics to an InDesign document, the most reliable method is the File, Place command, which enables you to control resolution, color, and some format-specific characteristics of graphics. (You can also use Place to add a text file to your document.) Figure 3.49 shows a list of those file types generated by Photoshop and Illustrator that can be placed into an InDesign document. Note the Show Import Options box. This option, by default, is not selected, although it gives you greater control over the artwork being added to the document.
Figure 3.49 Among the file formats you cannot place into InDesign are JPEG 2000, Raw, and Photoshop's Large Document Format (PSB).
Of the file formats that you can place into an InDesign document, there are only a few that you should place. Such formats as PICT, PCX, and WMF may be suitable for output to low-resolution inkjet printers, but they are not acceptable for commercial printing presses. Here are some points to remember when placing files in an InDesign document:
Photoshop, Illustrator, PDF, EPS (and the derivative format DCS 2.0), and TIFF should be the first choices.
For documents that will eventually be posted on the Internet, JPEG, GIF, and PNG can be used.
WMF and EMF files can be opened in Illustrator and saved as Illustrator, PDF, or EPS files.
BMP, PCX, PICT, and SCT files can be opened in Photoshop and saved as Photoshop, PDF, EPS, or TIFF files. All except Scitex (SCT) can also be opened in Illustrator and saved or exported in a preferred format.
Import Options for Placed Graphics Files
When the Show Import Options box is checked in the Place dialog box, placing Photoshop, TIFF, JPEG, GIF, BMP, PCX, and SCT files gives you the options shown in Figure 3.50. You can apply a clipping path (if one is embedded in the image) and elect how to color-manage the document (when ICC profiles are available).
Figure 3.50 When no clipping path or ICC profile is available, the Image Import Options dialog box does not appear.
The PNG file format includes one additional set of options, shown in Figure 3.51. If transparency has been designated in the image with an alpha channel or a specified color, you can use that information in InDesign. Gamma correction can adjust the tonality of an image to match that of a non-PostScript printer.
Figure 3.51 Remember that the PNG file format does not support CMYK color. PNG images will not separate.
The Illustrator and PDF file formats enable you to crop, preserve halftone screen information, and retain transparency in a placed image. The Place PDF Options dialog box is shown is Figure 3.52.
Figure 3.52 Because the Illustrator (AI) file format is based on PDF, it shares the Place PDF options.
If Show Import Options is selected when placing an EPS or DCS file, you'll see the dialog box in Figure 3.53. If a low-resolution proxy is embedded in the image, you can elect to use that for onscreen display by checking the Read Embedded OPI Image Links box. (Although a low-resolution version of the image will appear on the monitor, the actual high-resolution image will print.) If saved with the file, a clipping path can be used. You also have the choice of using an embedded TIFF or PICT preview or having InDesign generate a preview from the actual image data.
Figure 3.53 The proxy appearance has less to do with these options than it does with your choice of Optimized Display, Typical Display, or High Quality Display in InDesign's View menu.
When placing PICT, WMF, and EMF files, you have no Options dialog box.
Saving and Exporting InDesign Documents
When you use the Save command, InDesign creates (the first time) or updates (during subsequent saves) an InDesign document. The Save As command offers the option of saving as a template. You can also use Save As to assign a new name to the file, thus creating a copy. The Save a Copy command makes a copy of the file, document, or template and appends "copy" to the name.
InDesign's Export command enables you to save the document in a variety of formats. PDF and EPS are available for print-related projects. PDF, HTML, SVG, and compressed SVG are available for Web projects. InDesign can also generate XML, which is handy for projects that require multiple destinations, such as print, the Web, and PDAs.