Expanding Rectangular Selections
If you've ever tried to expand a rectangular selection by more than five or six pixels, you know what happens. The crisp, sharp-edged corners that you start off with become rounded. Here's the fix: Don't use the Expand command (found under the Select menu, under Modify). First, make your selection and press Command-T (PC: Control-T) to bring up the Free Transform bounding box. Go to the Options Bar and Control-click (PC: Right-click) in the Width and Height fields to change the measurements from Percent to Pixels. Now, simply add the amount of pixels you want to expand to the existing number. For example: If the field reads 110 pixels, and you want to expand it by 10 pixels, enter 120 pixels in the field and press Enter to apply the transformation. Don't forget to change both the Width and Height fields. That's itâ”perfectly expanded corners.