Easy Ways to Straighten an Image in Photoshop

Like most tasks in Photoshop, there are several methods you can use to straighten an image. In this tutorial, we are going to look at three of the easiest. We will cover using the:

• Ruler Tool to draw and automatically straighten an image.
• Crop Tool to crop and automatically level an image.
• RAW Filter which can straighten an image and correct all kinds of perspective problems.

We will examine each of the tools in turn, as well as considering their pros and cons when straightening an image.

It’s also worth taking a moment to clarify what we mean by “straighten an image”. In this tutorial, we’re talking about correcting the problem of the horizon in the image not being level. Looking for information about correcting more difficult perspective problems, I have other tutorials that might help? If you want to use Photoshop, look at my tutorial on fixing converging verticals. If you want to use Lightroom, try my tutorial about using the Transform Tool.

Checking the Horizons Level

Before we dive in to look at straightening a photo, how about first checking if the horizon is level or slanted? Whilst you don’t need to know if the horizon’s slanted or not to use the tools we discuss; you may find it can help. Here’s an easy way to check using the Guides in Photoshop.

Add a new Guide in Photoshop by selecting “View | New Guide…” in the menu. When the New Guides dialog displays, choose to add a new Horizontal Guide.

When the new Guide’s added, select the Move Tool from the Photoshop Tools Palette. This is the one that looks like a cross with an arrow at each end of the cross. If you can’t see it, it’s possible one of the other tools in the same group’s visible.

If you right-click the group containing the Move Tool, you will be able to see the tools in the group and select it.

With the Move Tool selected, you can click on the new Guide and drag it into position. In this next screenshot, you can see a horizontal guide in place, next to the image horizon.

The blue Photoshop Guide clearly shows the horizon in this image isn’t level and that the image needs straightening. Let’s look at how we can do that.

Using the Ruler Tool to Straighten an Image

Using the Ruler Tool is possibly one of the oldest methods to straighten an image in Photoshop. You will find the Ruler Tool in the Photoshop Tools Palette where it’s grouped with several other tools.

If the Ruler Tool isn’t visible, right-click the tool from the group that is visible and then select the Ruler Tool.

With the Ruler Tool selected, open the image you want to straighten. You then need to click and drag with the ruler. As you drag you will see a line appear. Try to line this up with something in the image that you want to be level, in this example it would be the horizon. You can see this in the following screenshot.

Whilst you’re drawing the line with the Ruler Tool, it may help your judgement if you magnify the image.

When you release your mouse button you will see the line you’ve drawn. If you didn’t quite line it up to match the area you want to straighten, you can click and drag the line at either end to reposition it.

Once you’re satisfied with your levelling line, click the “Straighten Layer” button in the Context Sensitive Toolbar.

Photoshop will then make the line you’ve drawn level by rotating the image, straightening it.

Whilst this approach is very easy to use it has a downside. You will need to crop your image to remove the space this creates around the edge of the frame.

Using the Crop Tool to Straighten an Image

Perhaps a better way to straighten an image is to use the Crop Tool. Quite a few versions back, Adobe added a Straighten feature to Photoshop’s Crop Tool, but it’s often overlooked. It’s easy to use and similar to the Ruler Tool we looked at above.

Start by opening your image in Photoshop and then selecting the Crop Tool from the Tools Palette. As with many of the tools, if you can’t see the crop tool, it’s possible one of the other tools in the same group is visible. You can see the expanded group below.

With the Crop Tool selected, click the image you want to straighten. This will apply the initial crop outline. Make any adjustments to the crop outline, before straightening the image.

Next, click the Straighten option in the Context Sensitive Toolbar. You can see this indicated in the screenshot below.

You can then click and drag out a line along the edge you want to straighten. This works just like the Ruler Tool but when you release the mouse button, Photoshop automatically rotates the image. The crop area is also resized to ensure there is no space around the edge of the image frame as you can see in the screenshot below.

If you’re satisfied with the result, click the tick icon in the Context Sensitive Toolbar. Alternatively, select the Straighten tool again and draw a new line.

Using the Straighten option in the Crop Tool is fast and easy. It’s a great way to remove image rotation without affecting the edges of the frame. But what if you need greater control and levelling the horizon isn’t the only task. That’s when our third method may help.

Using the Camera RAW Filter to Straighten an Image

This method is a little more work but far more powerful than the other methods of straightening an image. It involves opening the image using the Camera RAW filter that’s part of Photoshop.

Start by opening the image you want to adjust in Photoshop.

In the Photoshop menu select “Filter | Camera RAW Filter…”. This will open the image or image layer in Camera RAW. You can then click the icon for the Transform Tools from the toolbar along the top. You can see this in the screenshot below.

When you Select the Transform tools icon, you will see the tools displayed on the right of the interface. These give you complete control over levelling the image but also correcting all manner of distortions. Just move the Rotate slider left and right to level or straighten the image.

Covering the other options is beyond this tutorial but if you want to understand the different options, see my Transform Tutorial for Lightroom where the controls are the same.

Summary

In this tutorial, we’ve examined three easy ways to straighten an image in photoshop. The first two approaches using the Ruler and Crop tool are simple and effective but offer little control beyond rotating the image. The third using the Camera RAW Filter is also simple providing you only want to rotate the image. It is though much more powerful and allows you to correct all manner of distortions and problems.