We will look at a quick and easy way to straighten your photos in Photoshop.
We are all human and sometimes even the best of us have to account for a slight margin of error. Unless you shoot photos exclusively with a tri-pod or have a robot to place your items perfectly on a scanner, sometimes you need a slight bit of correction. You might even want to scan your artwork slightly crooked for a discerning technique. For whatever reason you have, Photoshop makes the process of leveling them out easy as 1-2-3.
First let us start with our example photo. I have taken the liberty of making this picture overly rotated. Yikes that needs a good straightening!
The first thing we will want to do is select our ruler tool from the tool bar. You can access this on a fly out menu on the Eyedropper tool by clicking and holding till the fly out appears, or alternately you can cycle the tools by pressing Shift+I (this will cycle through all the tools under the Eyedropper)
Now that we have our Ruler Tool at the ready we need to find a good straight edge to use. For this example I chose the edge of the door as we know that that point is supposed to be straight. Alternatively we could have used where the bricks met the door. Either will work, we just need a line that will be perfectly horizontal or vertical.
At this point we have to choices on how to proceed. We can use the Rotation Menu or the Options Bar. What one you use would be determined on if you would like to rotate all your layers and increase the canvas size to the edge of your photo or a single layer while not altering the canvas size.
Rotation Menu – Rotate All Layers And Increase The Canvas Size
From the File Menu at the top of the screen choose Image>Image Rotation>Arbitrary…
this will bring up the Arbitrary Rotation dialog however you will notice that values have already been placed inside. The Angle will have values and the Clockwise or Counter Clockwise button will already be chosen based of the angle we measured from the Ruler Tool.
This will rotate the whole image area and add to the canvas size. This will rotate any additional Layers you have in this job
Options Bar – Single Layer While Not Altering The Canvas Size
On the options bar while you have the Ruler Tool selected you will notice a button labeled Straighten Layer.
Clicking this button will rotate the active layer or if the image is on the background it will convert it to a single layer.
The canvas size will not be altered in any way. If you would like to expand the canvas area to the edges of the cropped photo you can always use Reveal All located in the File Menu under Image>Reveal All
At this point you may want to crop or re-position your photo or scan to suit your needs.