Cropping
Since the original shot of the crab is a bit misty, we will first adjust the Levels and colors.
Original
After color adjustment
After cropping
Levels Adjustment
From the Photoshop menu bar, select "Enhance > Auto Levels" or press "Shift+Ctrl+L". The result is not bad, but we further adjust via "Enhance > Adjust Lighting > Levels", or by pressing "Ctrl+L"to bring up the Levels dialog box. Remove the blue cast by sliding the midtone slider of the blue channel to 0.85 and then make the tone a bit warmer by sliding the midtone slider of the red channel to 1.15. Look at how much detail we pulled out of this initially very misty picture! The sand in the corner and around the edges of the image is more blur and we will crop this away on the next page.
Cropping
Use the Crop Tool to crop away the edges as indicated in the animation below. First draw the general outline by dragging the Crop Tool over the desired area. Adjustments to the initial selection can then be made by dragging the little squares at the corners and edges of the selection area. If you place the pointer inside the selection, you can drag the selection to its final position. When you are happy with the result, double-click on the selection or press "Enter".
Note that when you crop you will lose resolution. The initial 2,048 x 1,536 three megapixel image is now at 1,600 x 1,200, only 2 megapixel. While this is not important for web publication, it is a critical difference if you do larger printouts. Chapter 11 (in the Full Version) shows another cropping example where cropping enhanced the speed effect in an action shot.
Normally it is best to first crop before doing any Levels adjustments, because the areas you will be cropping away may (negatively) influence the Levels adjustments. In this example it did not matter as the image was uniform.
This tutorial can also be applied in Adobe Photoshop CS4-CS3-CS2-CS and other image editing software.
