Navigation in Photoshop is a very import aspect of retouching. It's important that we're able to quickly zoom in/out, move the canvas or compare the retouched part of an image with the original.

It's easy to zoom in/out in Photoshop if we have a wheel mouse; rolling the wheel away from us allows us to zoom out, rolling the wheel towards us allows us to zoom in. Note: sometimes you need to hold down the Alt key (option key on the Mac) when you use the scroll wheel, I think it's a glitch in Photoshop. So if you want make sure it always works, just hold down this key like I always do.
Sometimes we want to zoom in with a specific percentage. We can do that for example by using the status bar:

In this example we can change the value 89,21% to 200% by entering a value of 200 and pressing enter.
Sometimes this status bar is disabled and in that case you have to go the menu and select Window / Status Bar to enable it ( will appear in front of it). Note: in Photoshop CS2 every single document window has its own status bar, in earlier versions there's only one status bar for all images (at the bottom).

You can quickly zoom in to 100% by double clicking on the Zoom Tool icon in the tool bar. The same can be achieved by pressing Alt + Ctrl + 0 (read 'zero') in Windows or Option + Command + 0 on the Mac.
Zooming in to 100% ( 1 to 1 view) is important if you want to have an undistorted view on your pixels. Let me show you what I mean;

Zoom factor 100%:

Zoom factor 90%:

Zoom factor 110%:

 

In the original image at 100% we see a smooth line. Zoom out to 90% or zooming in to 110% creates artifacts in our document window.

But then again, any resampling of an image, whether you're using zoom or Image / Image Size in your menu has a negative effect on the quality of your image. The only difference is that after using Image / Image Size these artifacts are final, but not when we're just viewing with the wrong percentage. Viewing an image doesn't effect the image in any way, so don't you worry if you see these artifacts at other zoom levels than 100%, because they're only visible in your document window.

We can also fit our image inside our current document window and we do this by double clicking on the Hand Tool icon (shortcut is H) in the tool bar. The same can be achieved by pressing Ctrl + 0 (read 'zero') in Windows or Command + 0 on the Mac.

When the Zoom Tool is active you'll also notice 3 buttons in your options bar:

The Actual Pixels button also allows you to zoom in at 100% and the Fit On Screen button allows you to fit the image inside your document window, like we did earlier by double clicking on the Hand Tool icon (or using the shortcut). The Print Size button displays the pixels at the size it will print ( see Image / Image Size... ).

We can also use Photoshop's Navigator Palette to navigate our image. If the navigator palette is not visible, then you have to enable it first in the menu by going to Windows / Navigator.

Let's have a look at the navigator palette:

In the box marked with A we can enter the zoom factor which is currently 81.97%. Only values between 0.11% and 1600% are allowed.

We can also use the slider marked with E to zoom out by moving the slider to the left or zoom in by moving it to the right.

By clicking the iconmarked with B we're able to zoom out in small steps. Clicking on the icon marked with C allows us to zoom in. The red square marked with D tells us which area of the image will be visible in our document window and will get smaller and smaller the more we zoom in. We can move this square by moving our mouse cursor over the square until a little hand appears. When that happens you just hold down the left mouse button and move the square to reveal a different part of your image in the document window.

Note: you can only move the square if it's smaller than the image itself (in case you wonder why the little hand cursor doesn't appear when you move over the square). Look at the screenshots; in the left image we're not able to move the square and in the right image we have no problem to do this:

 

Important to mention is that we can resize the navigator panel by clicking and dragging the lower right corner that I have marked in this screenshot:

 

This allows us to see a lot more details:

 

Another way to zoom in or out is by using the Zoom Tool (shortcut is Z) in the options bar. Open an image, select the zoom tool and move the cursor over the image; the cursor will turn into something like this , which means that we can now zoom in by pressing our left mouse button once. Hold down the Alt key (option key on the Mac) and the cursor changes to and we're now able to zoom out by pressing the mouse button again.

You can also use the Zoom Tool when it's not active. Click for example on the Elliptical Marquee Tool icon . Now hold down Ctrl + Space Bar (Command + Space Bar on the Mac) and you can zoom in. Press on the Alt key (Option key on the Mac) while still holding down these two keys and you can zoom out. Release all three keys and Photoshop returns to the Elliptical Marquee Tool. You can also zoom in while the Elliptical Marquee Tool is active (or any other tool) by using the scroll button on our mouse while holding down the Alt key (Option key on the Mac)

We can also zoom in/out pressing Ctrl and + or Ctrl and - (Command +/- on the Mac), no matter which tool is active.

Zooming in on one particular area in an image is easy. Select the Zoom Tool icon in the Tool Bar and use the mouse to select the area that you want to magnify...

...and release the mouse button. Note (for those absolutely new to Photoshop): selecting is done by clicking one corner, holding down the mouse button, moving the mouse to drag the opposite corner of your selection and releasing the mouse button when you're done.

If your image doesn't fit in your document window, then you have to select the Hand Tool in the toolbar and use your mouse to move your image by clicking and dragging it inside your document window.

The following shortcut is not only easy but also important to remember: the Space Bar. The Space Bar allows you to select the hand tool at any time, no matter which tool is selected. By releasing the Space Bar you return to the tool that was previously active.
I also want to mention that the Space Bar does more than just moving the canvas. Open an image, grab the Elliptical Marquee Tool icon and draw a selection but don't release the mouse button yet. Instead hold the space bar and then move your mouse cursor. You'll notice that by holding down the space bar you're able to move the selection.

The space bar is such a useful shortcut, that I don't even feel the need to mention how you can scroll sideways or up and down using the Page Up and Down keys in combination with (in my opinion) hard to remember shortcuts. The Space Bar however is a lot easier to remember and does the job just fine.

Another way to move your canvas is of course by using the navigator and moving the red square like we saw earlier.

Open any image and go to the menu and select Window / Arrange / New Window for ......... . ... :

What this does is that it opens a new window for your current image. It does not duplicate the image under a different name. Look at it as having 2 views on the same image. This allows us to work in great detail with higher zoom levels and see the effect of our corrections in a smaller view of the same area we're working on:

 

This can be very useful, because what might look like a natural looking result of a correction at 300% for example, might look manipulated at 100%. I would also like to add that you're not restricted to 1 extra window, you can have lots of them:

Just remember that you're not working with 4 different files at that time, just 4 different views. In this example I added a red dot to the eye and it will show in all views, because like I said, there's only one image we're working with.

I hope that you enjoyed this tutorial.

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