In this article, we first explore some of the fastest ways to move around your image, including zooming in and out. Then we discuss moving pixels around both within your document and from one document to another. Even expert users forget (or never learn) this basic stuff, so we urge you to read this article even if you think you already know all there is to know about navigating Photoshop.
Images have pixels. Computer monitors have pixels. But how does one type of pixel relate to the other type of pixel? When one image pixel is displayed on one monitor pixel, you’re seeing every detail of the image. In Photoshop, this happens at 100% magnification, or with the Actual Pixels command under the View menu. This view doesn’t necessarily tell you how big the image will appear in print or even on the web, however, because different monitors have different resolutions.
At 400%, the image is magnified four times, so each image pixel is displayed using 16 monitor pixels (see Figure 1). At 50%, you’re seeing only one-quarter of the pixels in the image, because zooming out causes Photoshop to downsample four image pixels to one monitor pixel. At any percentage other than 100%, you’re not seeing a fully accurate view of your image, because you aren’t seeing the exact number of pixels in the image.
Figure 1 How magnification affects the image detail you see.
When you’re viewing at an integral multiple of 100% (25%, 50%, 200%, 400%, and so on), Photoshop displays image pixels evenly. At 200%, four screen pixels (two horizontal, two vertical) equal one image pixel; at 50%, four image pixels equal one screen pixel, and so on. However, when you’re at any "odd" percentage, the program has to jimmy the display in order to make things work. Photoshop can’t cut a screen pixel or an image pixel in half, so instead it fakes the effect using anti-aliasing. Magnifications lower than 100% can give you a distorted view of resolution-dependent effects, such as sharpening.
The moral of the story is that you should always return to the Actual Pixels (100%) view to get the most accurate view of your image. You’ll be doing this all the time, so learn the shortcuts:
- Command-Option-0 (zero) for Mac
- Ctrl-Alt-0 (zero) for Windows
- Double-click the Zoom tool in the Tools palette
Zooming the View
We never select the Zoom tool from the Tools palette, because that takes too long. You can temporarily switch to the Zoom tool by holding down Command-spacebar to zoom in or Command-Option-spacebar to zoom out (Mac), or Ctrl-spacebar to zoom in or Ctrl-Alt-spacebar to zoom out (Windows). Each click is the same as choosing Zoom In or Zoom Out from the View menu.
Here are some other useful zoom notes:
- Drag to zoom. When you drag a rectangle by using the Zoom tool, the area you drag magnifies to fill the window.
- Zoom with keyboard shortcuts. If you just want to change the overall magnification of an image, zoom in and out by pressing Command-+ (plus sign) or Command-- (minus sign) in Mac OS X, or by pressing Ctrl-+ (plus sign) or Ctrl-- (minus sign) in Windows. When zooming, the window won’t extend under the edges of palettes; if you want this to happen, use one of the Full Screen modes. In Mac OS X, adding the Option key to this mix tells Photoshop to zoom in or out without changing the size of the window. For some reason, it’s just the opposite in Windows: The Ctrl key zooms without resizing, and holding down Ctrl and Alt zooms and resizes. In any case, if you want the opposite behavior to be the default, disable the Zoom Resizes Windows checkbox in the General Preferences dialog.
- Zoom with the scroll wheel. If your mouse has a scroll wheel, you can use it to scroll or zoom. By default, it’s set to scroll, and pressing Option (Mac) or Alt (Windows) makes the scroll wheel zoom instead. To reverse this behavior, check Zoom with Scroll Wheel in the General Preferences dialog.
- Fit the image within the screen. Double-clicking on the Hand tool is the same as clicking Fit Screen in the Options bar when the Zoom tool or Hand tool is selected, or pressing Command-0 (zero) on Mac or Ctrl-0 (zero) on Windows. That is, it makes the image and the document window as large as it can without going outside the screen’s boundaries. Note that the image may not zoom to the full width or height of the monitor if palettes are present.
- Use the Zoom field in the document window. At the lower-left corner of the window, Photoshop displays the current magnification percentage. This isn’t only a display; you can change it. Double-click to select the whole field, type the zoom percentage you want, and then press Return or Enter. If you’re not sure what percentage you want, press Shift-Return instead of Return, and the field will remain selected so that you can enter a different value (see Figure 2).
Figure 2 Use the Zoom field to tinker with the zoom value.
Using Print Size Magnification
Generations of Photoshop users have been baffled by the View > Print Size command, mostly because when you choose it, it never matches the size of the image when you actually print it! The only way the Print Size command can know the actual print size is to know the resolution of your monitor, so that the rulers become accurate. To make Print Size work correctly, follow these steps:
- 1. Open the Displays system preference (Mac) or the Displays control panel (Windows), and note your monitor’s current resolution setting (for example, 1280×854 pixels).
- 2. Grab an actual, real-world ruler and measure the width of your monitor image (not the frame in inches). Be careful not to scratch your screen!
- 3. Divide the horizontal pixel dimension of your monitor by the horizontal real-world dimension of your monitor. For example, my widescreen LCD monitor is set to 1680 pixels across a physical width of 17 inches, and 1680/17 = 98.8 pixels per inch.
- 4. Open the Preferences dialog, click the Units and Rulers pane, and enter your pixels per inch value into the Screen Resolution field (see Figure 3).
Figure 3 Setting screen resolution for accurate print-size viewing.
Now, when you choose View > Print Size, Photoshop can take into account both your screen resolution and the resolution of the image in the Image > Image Size dialog, and correctly display the printed size of the image. Another wonderful result of all this effort is that your rulers now match the real world at Print Size magnification. If the rulers don’t match exactly, adjust the Screen Resolution field slightly until they do.