Getting perfectly straight or level photos can be hard in some circumstances. Uneven ground or an off-centred camera can result in a crooked photo, and lower its quality. Using Photoshop, we can correct for these errors and create an accurately cantered and well-leveled photo.
Step 1: Opening the ImageOur first step is to open our image that we want to level or straighten out. The photo needs to have some visual elements, that when taking it where straight either horizontal or vertical straight.
For example edges of buildings/structures, horizon lines, etc. which should have a straight edge that we can use as a reference. In my case, I am using the photo below. When taking the photo, the building structure was straight, but unfortunately the ground was not, and I am left with this off-angled photo. However, this building is perfect to use as a reference to adjust my image.
Step 2: Using the "Ruler Tool or Measurement Tool"Using the Ruler/Measurement tool (I), or within CS5 you can go via the menu: Analysis > Ruler Tool, we want to draw a line along a straight edge that we wish to re-orientate in the photo. I am going to use the edge of this building because I know this should be straight and aligned to the vertical axis.
Step 3: Method One, "Straightening" (CS5)Using Photoshop’s inbuilt method of straightening is one way to correct the photo. With the line drawn and the ruler tool still selected, click the “Straighten” button on the ruler tool menu below the main menu bar. This should automatically straighten the image and accurately fit it to the line you drew. The tool also crops the image for you, removing empty space created by skewing the image in order to get it straight.
Step 4: Method Two, "Arbitrary Rotate" (CS2+)Another and just as effective way to fix an image using the ruler tool is to do an arbitrary image rotation. With the line from the ruler tool still drawn on the unlevel photo, apply an “Arbitrary Rotation” (Image > Image Rotation > Arbitrary). Photoshop automatically finds the angle needed to rotate the canvas so the line is perfectly straight, and inputs this into the field. Select “Ok” while leaving the fields as they are.