Using Guides to Crop after Leveling

by Hugh Stockton

After you have used the Measure Tool to level your horizon or make your buildings vertical, you are left with a tilted image but a square frame. You now need to crop the odd pieces off of the image and you typically want to crop off only as much as necessary without leaving any of the frame showing. This tutorial shows how to use the Photoshop Guides to do so precisely and simply.

1. Level the image with the measure tool - http://www.shutterfreaks.com/Tips/LevelHorizons.html. This will leave something like this:
   
   
   
   
   
2. Select View>New Guide...>Vertical>OK from the Photoshop menu. That will produce something like this. I've zoomed in so you can see the guide.
   
   
   
   
   
3. Now use the Move Tool (V) to align the guide with the edge of your intended crop.
   
   
   
   
   
4. Use the Rectangular Marquee Tool (M), starting from the logical frame/image/guide intersection to encompass the maximum amount of the image without 'marching ants' visible on the frame.
   
   
   
   
   
5. Image>Crop to remove the excess image.
   
   
   
6. Click in the gray to remove the marching ants.
   
   
   
7. View>Clear Guides to remove the guide.