Saving Your Work
| There's one very important thing to know about saving your work: Do it often! Computers are prone to unexpected shutdowns and errors. Saving takes only a couple of seconds, and it can make the difference between having to do your work all over again or just reopening it if the computer shuts down. The first time you save a picture, you'll see the Save As dialog box, as shown in Figure 2.5. Give the file a name and select an appropriate format to save it in from the pop-up menu. After this, click Save or just press Command+S (Mac) or Control+S (Windows) to save the file. Figure 2.5. Saving a file in Photoshop.
In addition to the familiar Save and Save As commands, Photoshop has more Save commands, such as Save a Copy. This option is found in the Save As dialog boxcheck As a Copy to use it. Save a Copy, like Save As, lets you save the file with a new name and in a new location. The difference is that after you use Save As, you're working in the new file. If you use Save a Copy, you save a copy of the file as it is at that moment, but you'll still be working on the original file, not the copy. Save a Copy is especially useful for making a backup copy before you try a drastic change, such as reducing color depth or increasing JPEG lossiness, or for saving the file in a different format. Suppose that you create a logo for your business and want to use it in print and on the Web. You'd save it as a TIFF or EPS file to print from, and you'd save a copy as a JPEG or PNG file for your Web page. The word copy is automatically added to the filename. The final Save option, located in the File menu, is Save for Web. It contains the settings you need to optimize the image for Web use, including letting you see and select the amount of JPEG compression to apply, so you can get the smallest file that won't compromise the image quality too much. You can save Web images either in Photoshop or in ImageReady. It makes little difference, unless animation and other special Web effects are involved, in which case you'll probably want to use ImageReady. You'll learn about these options in detail in Hour 24. Reducing File SizeAs you start to work with different Photoshop files, you'll notice that your hard drive is starting to fill up. Photoshop files can become large very quickly. You can make your files smaller in several ways:
Reducing the resolution is not a good idea if you're going to print the image. If the picture is going to be viewed only on your computer screen or on the Web, reduce the resolution to 72 dpi. Be aware, though, that increasing the resolution again, if you change your mind, reduces image quality. You can change the resolution in the Image Reducing the number of colors means reducing the bit depth. This can make your colors look blotchy onscreen and in print. If you are working in grayscale (no color in the picture), reduce the bit depth to 8 bits by choosing Grayscale in the Image Mode submenu. This gives you 256 shades of gray, which is more than a printer can print. Using a compressed format means choosing a file format, such as TIFF with LZW compression, that automatically shrinks the file down as small as possible when it saves. It does this by a means called lossless compression , so there's no image degradation or blotchy color. LZW compression (named for its inventors, Lempel, Ziv, and Welch) is also used by GIF and PDF formats. There are also formats, such as JPEG, that use lossy compression . Lossy means, as you might guess from the name, that some of the data that makes up the image is lost in the compression process. Instead of 20 shades of blue in the sky in a TIFF file, the same image in a JPEG file might have only 5 shades of blue. And, yes, you can see the difference. Unfortunately, compression is necessary when you are placing images on the Web, in a multimedia presentation, or in another situation where upload time or storage space is limited. JPEG saves files in the least possible amount of disk space. One point to remember is that if you save a JPEG image a second time as a JPEG, it is compressed again and loses more information. If you work on a JPEG file a lot, you can end up with an unreadable picture. If you're going to work on a picture, save it as a Photoshop file. Don't make it a JPEG until you're done with it and ready to post it on your Web page. If you have to change the image, trash the JPEG file and go back to the Photoshop version. When you have files you want to save for future reference, you can save them in the normal way as Photoshop documents (with a .psd filename extension) or in whatever format you prefer to work in, and then compress the files with a utility such as StuffIt or PKZip or WinZip. All these file compression utilities use lossless compression algorithms and shrink your image files by anywhere from 20% to 50%. That said, compressing JPEG or GIF files is relatively useless because they're already compressed. You won't gain more than a few percent of additional compression. Figure 2.6 shows a typical digital photograph that I saved in a number of different file types. (The original is about 5 inches wide, and saved at 200 dpi.) Table 2.1 shows the more common file types and the sizes of the files that this picture required. The version shown is a PSD, the native Photoshop format. Table 2.1. File Format/File Size Comparisons for Figure 2.6
Figure 2.6. If storage space isn't a problem, don't compress the picture. Choosing a FormatWith so many possible formats, how can you decide which one to use? It's really not so difficult. As long as you are working on an image, keep saving it as a Photoshop document ( .psd ). This makes sense, especially after you learn to work in layers, because Photoshop's native format can save the layers, whereas most other formats require that you merge the layers into one. After you have flattened the layers, you can't split them apart again. So, bottom line, as long as you think you'll want to go back to a picture and modify it, save a copy as a Photoshop document. When you finish working on the picture and are ready to place it into another document for printing, save a copy as an EPS file if it's going to a PostScript-compatible printer. If you aren't sure how it will be printed, save it as a TIFF because TIFF is compatible with most printers and page-layout programs. If you're going to place your picture on a Web page, choose GIF if the picture is line art, has large areas of solid color, or uses a limited color palette. Choose JPEG or PNG if the picture is a photograph or continuous tone art (lots of colors). If you want to import the picture into some other graphics program for additional work, choose Photoshop format (PSD) if the other program supports it, and TIFF if the other program doesn't recognize Photoshop files. |
Image size dialog box. Dont make it less than 72 dpi. 
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