SAMS Teach Yourself Adobe® Photoshop® CS2 in 24 Hours [Electronic resources] نسخه متنی

Working with Files

Photoshop can open and save images in many file formats.

Formats are ways of saving the information in a file so it can be used by other applications, printed, or placed on a Web page for use on the Internet.

In the Windows world, file formats are defined by three-letter extensions to filenames, such as .doc for a word processing document and .bmp for a bitmapped graphic. Because you can toggle off the extension codes in Windows, you actually might not see extensions to known file types. Rest assured, they are there.

Macintosh users really only need to use file extensions if they're sharing files with someone on a PC, or are posting them on a Web page. You can toggle Append File Extension on or off in the PreferencesFile Handling dialog box.

The most commonly used file format in Photoshop is its native format. The extension is .psd (Photoshop document). The drawback to working in "native Photoshop" (.psd) is that other applications might have trouble opening this format. To move files between applications, to print, or to publish on the World Wide Web, you must save your files in a compatible format.

A new file format called Large Document Format (.psb) was introduced in Photoshop CS. It's meant to be used for handling very large files. (You might remember the extension more easily if you think of it as Photoshop Big.) This format was developed to meet the needs of all of the multi-mega pixel digital cameras in use, and to let you work with, and save, multiple layers in a large document. Because it's new, it's not backwards compatible. Anything you save as a .psb file can only be opened in Photoshop CS. You can toggle the format on or off in the PreferencesFile Handling dialog box. If you share files with users of older editions of Photoshop, leave it off.

The following are some common formats with brief definitions of their uses. Note that Photoshop can handle many other graphics formats as well.

• Bitmap ( .bmp

  ) .
  This is a standard graphics file format for Windows.

• GIF ( .gif

  ) .
  GIF stands for

  Graphics Interchange Format . It is one of the three common graphics formats you can use for Web publishing. Because it is a compressed format, it takes less time to send by modem.

• JPEG ( .jpg

  ) .
  JPEG stands for

  Joint Photographic Experts Group . JPEG is another popular format for Web publishing.

• PDF ( .pdf

  ) .
  Adobe Acrobat's

  Portable Document Format , a system for creating documents that can be read cross-platform.

• PNG ( .png

  ) .
  Stands for

  Portable Network Graphic . It's a newer and arguably better format for Web graphics, combining GIF's good compression with the JPEG's unlimited color palette. However, older browsers don't support it. (We'll discuss these formats and their use in Web publishing in Hour 24, "Photoshop for the Web.")

• TIFF ( .tif

  ) .
  TIFF stands for

  Tagged Image File Format . These files can be saved for use on either Macintosh or Windows machines. This is also often the preferred format for desktop publishing applications, such as InDesign and QuarkXPress. When you save a TIFF file, you can choose whether to include layers. If you do include layers in a TIFF file, the image might not be compatible with all desktop publishing programs.

• EPS ( .eps

  ) .
  

  Encapsulated PostScript is another format often used for desktop publishing. It uses the PostScript page description language, and can be used by both Macintosh and PC.

• Raw (usually .raw

  ) .
  This format saves image information in the most flexible format for transferring files between applications, devices (such as digital cameras), and computer platforms.

These file formats, and some less common ones such as Targa and Scitex CT, are available in the Save dialog boxesFileSave and FileSave As. Just look for the Format pop-up menu. Figure 2.1 shows the Save As dialog box with the formats available.

If you work on a Macintosh and need to share files with non-Macintosh usersor if you just like to stay on the safe sidego to the PreferencesFile Handling dialog box. Click the check boxes to add an extension and to keep it in lowercase (as required by some older software).

Opening Files

Opening a file in Photoshop is as easy as opening it in any other application. You can open as many images as you want or as many as your computer's memory can hold. If a file is of the proper type (a file format that Photoshop recognizes), all you have to do is double-click it with your mouse to not only open it, but to launch Photoshop as well. (If Photoshop is already open, you can either double-click a file or use the FileOpen command.) You can also drag and drop a compatible file onto the Photoshop CS2 icon to open the file.

Windows Users Take Note A technical note for Windows users: Double-clicking an image file will open Photoshop only if the extension (.bmp, for instance) is associated with Photoshop. Sometimes, installing new applications will change the extension mapping to other programs. GIFs and JPEGs are notoriously remapped to Microsoft Internet Explorer, whereas BMP is usually grabbed by Paint. If double-clicking doesn't work for you, check your extensions.

When you open the dialog box, Photoshop displays all the files that have formats it can open. Figure 2.2 shows the Photoshop Open dialog box. As you can see, if you click Preview, Photoshop will display a thumbnail of the selected image. To create previews, go to PreferencesFile Handling, and choose Always Save Image Previews.

Using Bridge

If you have only a few graphics files, and if you're really good at keeping things organized, finding the document you're looking for isn't difficult. If, however, you're like me, your files are all over the place, and saved with the apparently random numbers the camera assigns. That's why Photoshop CS2's Bridge is one of my favorite features. To open it, use FileBrowse. See Figure 2.3.

Click a tab at the upper left (Favorites or Folders) and navigate through the folder hierarchy to locate the folder you want. As soon as one is selected, you'll see all its images displayed as if on a slide viewer. If there are folders nested inside the one you originally opened, you'll see them as folder icons. The upper-left section of the window shows the location of the file you opened. If your digital camera or scanner saves information about the selected image, you can scroll through the lower section to determine what lens and shutter settings the camera used, whether the exposure required a flash, and the precise minute and second the picture was takenvirtually everything you need to know except where it was shot. Actually, there are now some special-purpose digital cameras with GPS connections that

can tell you where the picture was taken.

Then just scroll through the folders and the images within them until you find the one you want. Double-click the thumbnail image in the right section of the window or the preview on the left to open the original.

Importing a File

The Import command (FileImport) lets you open files that have been saved in formats that use plug-in import modules, as well as files that aren't on your hard drive. Typically, these include images created with your scanner or digital camera and special image types such as PICT resources (Macintosh only).

Importing from Digital Cameras

Most digital cameras can import pictures directly into Photoshop. The plug-in filter or photo browser comes with the camera. Drop it, if the directions say to, into the Plug-ins folder. (Remember that you must quit the application before you install plug-ins. If you install while Photoshop is running, it can't see the new plug-in until you quit and restart the program.) To import a picture, you simply plug the camera cable into the computer's USB port. Then choose FileImport and whatever camera you are importing from. Pictures in the camera are displayed, as in the Photoshop Browser, as if they were slides on a sorting table. You can view a larger image and find out more about it by selecting a picture and double-clicking or choosing Get Info. You can't click the picture and expect it to open into Photoshop, however. It will open into its own full-screen display. To work on it in Photoshop, you must open it from within Photoshop.

Mac OS X users can also open photos from iPhoto, a Mac application that doesn't require any additional software to download from all kinds of digital cameras. Figure 2.4 shows a small collection of photos imported directly from a Nikon CoolPix 5700. It's very easy to build photo libraries with this program, and you can import the pictures you have worked on in Photoshop for an easy slideshow.

Camera Raw

Camera Raw is a format that Adobe added as a plug-in in 2002, and sold separately. Because it proved to be useful and popular, it's included in Photoshop CS2. Essentially, what it does is enable direct downloads from a digital camera, without translating the file into JPEG. It takes the raw camera data, and gives you, in effect, a digital "negative." You can assign color corrections, sharpen the focus, compensate for spherical lens aberrations, and make other needed corrections picture by picture as they are copied into the computer.

Importing Files with the TWAIN Interface

The TWAIN Acquire and TWAIN Select commands found under the FileImport submenu don't actually import images. Instead, they enable you to open the appropriate scanner software to be used from within Photoshop and to use it to import the scanned images. Photoshop supports TWAIN, TWAIN32, and TWAIN_32 standards for scanning. Consult the scanner manual for more information.