How To Correct Sloping Horizons :: Digital Photo Secrets

How To Correct Sloping Horizons

by David Peterson 2 comments

If you haven’t mastered the perfect camera grip quite yet, your photos of ordinary buildings can start to look like the Leaning Tower Of Pisa pretty quickly. With sloping horizons, something always feel just a little bit “off” about your photos. Luckily, there’s a way to change that in short order. With a few simple editing tools like Photoshop, you can quickly straighten out your leaning photos and get back to working on that iron camera grip of yours.

To get started, you want to have the right photo editing software. There are a lot of software packages that help you straighten your photos. In this tutorial, I will cover both Picasa and Photoshop. Straightening is actually pretty easy to do once you’ve figured which tools to use. After your first few sessions, it’ll be a snap.

Straightening In Photoshop

To start, open your image in Photoshop. I’m using Photoshop CS, but because this is such a basic adjustment, it is the same in any version of Photoshop including Elements.

Once you’ve got your image opened, set up some rulers. Go to the view menu and select “rulers.” This will give you the horizontal and vertical rulers you will use to find out where you want to place your horizontal guide. If this sounds confusing right now, bear with me. It’ll all make sense soon.

The next part is a little tricky. You want to find a part of the image that should be perfectly horizontal. That’s the horizon line. You’ll notice that there is a nice horizon line in the photo below, so I’m going to place my horizontal guide right along the horizon.

To do this, you go to the view menu once again and select “new guide.” You will be given two choices, both horizontal and vertical guides. Because we are adjusting the horizon, pick the horizontal guide. Your guide has to be somewhere near the horizon line. Then use the move tool to move the new guide onto your horizon.

Here’s the same image with my guide.

As you can see, my horizon line is not quite level. The sea is slightly below the line on the right of the image while right on the line on the left side. Don’t worry about the blue guide line appearing on your image when you print or save it. Photoshop knows to get rid of it.

When you want to actually straighten your image, you go to select and then click on “all” (also ctrl + A). Next, go to edit, select “transform,” and select “rotate.” Once you’re in rotate mode, you can rotate the image any way you like by clicking to the outside of a corner of your image. When your horizon line and the horizontal guide match up, your image is now horizontally aligned and it’s time to move on to the next step.

Cropping After Rotating

Because you have rotated your image a little bit, the corners won't be properly aligned anymore and you'll see some plain background color at the edges. To avoid this problem, crop your image and save a new version. It’s an easy fix. Just pick the crop tool and select as much of the image as you can without selecting any of the background color that shows.

With your selection made, press Enter or click on the tick at the top of Photoshop This crops your image to the dimensions of your selection.

Your rotated and cropped image is done! Select Save As to save a copy of this picture (make sure you don't overwrite your original!)

Straightening In Picasa

It’s a lot easier to straighten your photos with Picasa. You simply open up the application, double click on a photo you want to straighten, and then choose the “straighten” option under “basic fixes.”

Picasa’s straighten tool overlays a grid on your photo. You’re given a slider you can move to the left or to the right, and as you move it, the camera zooms in even further to help you line up the horizontal lines with the grid.

In this image, I picked the white line created by the landing of the jump. I moved the slider ever so slightly until it matched up perfectly. Once I was finished, I clicked on the “apply” option, and my work was done.

After having used both Photoshop and Picasa for quite some time, I have to say Picasa is better for quick adjustments, and Photoshop works really well when you need to be extra precise. In Photoshop, I can pick where I want to place my horizontal guide, but Picasa won’t let me do that. If there isn’t a horizontal line on the grid that matches up with my image, I can’t do anything about it.

Picasa and Photoshop aren’t the only photo editing programs out there, but they are some of the most accessible. You can download Picasa straight from Google, free of charge. That’s pretty awesome when you consider how easy it is to straighten your photos with it.

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  1. ben says:

    It's a pity that you never addressed the "Straightening Tool" in Photoshop Elements 15.
    Apart from that point, great work and keep it up.

  2. Charles Cron says:

    Windows Photo Gallery has a system similar to Picasa and is very easy to use. I have read Google plans to discontinue Picasa in the near future. Windows Photo Gallery also does not work with Windows 10.( I tried W 10 but went back to W 8.1 as I could not access my photos in the Gallery. Any comments?
    Also, how can this be done using the Gimp, a free on line program similar to Photoshop without the cost.Thank you.CC.

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