How to Straighten an Horizon in Photoshop using the Measure Tool

How to Straighten an Horizon in Photoshop using the Measure Tool

Mandy Post processing 4 Comments

How to Straighten an Horizon in Photoshop using the Measure Tool solved my bad habit

If there’s one bad photography habit that I’ve got that really annoys me it’s shooting wonky horizons.

I’m forever doing it, I could swear it was straight when I took the shot but when I check it’s off again!

I don’t know maybe one of my legs is shorter than the other? Or maybe I’m just wonky?

Or maybe it’s just a detail that I’m not spending enough time on to make sure it’s right?

I like to get things right in camera rather than just rely on ‘it’s ok I’ll fix it later’ attitude.

So what I generally do in camera to stop myself doing this, is to line the horizon up with one of the lines of auto focus points in the viewfinder, and that works really well.

But for every other time when one slips through the net here’s how I straighten the horizon in Photoshop:

Rotate canvas

rotate canvas

rotate canvas – arbitrary

What I’ve always done is use the rotate canvas option from the image menu and choose arbitrary, then choose how much to rotate it by and in which direction (clockwise or counter clockwise).

Generally it’s not much (0.x).

Basically I’m doing it by eye (which can’t have been that good in the first place or I wouldn’t be doing this! or I’ll get it right this time because I’m actually concentrating on it!).

Because there’s a bit of guess work involved it can take 2 maybe 3 goes before I’m happy with it.

but…. is there another/better way….

… of course there is!

Measure tool

measure tool

find the measure tool

So although I enjoy my little tweaking in rotate canvas, I’ve recently come across a more time efficient and exact way of straightening my images using the measure tool.

I’ll walk you through it –

In Photoshop go to the eye dropper tool in the tool box and right click to get more options, go to the bottom and choose the measure tool.

Then click on one end of the horizon and drag (draw a line) to the other end of the horizon. So the line that you’ve drawn matches the horizon in the image, as shown below.

using measure tool

using measure tool

Once that’s done go to image menu – rotate canvas – arbitrary. When the box appears you’ll notice that there is already a number in it, in this case 3.41. Photoshop has automatically worked out how much it needs to rotate the image to make the horizon (what you measured with the measure tool) horizontal.

arbitrary tool

arbitrary tool already filled in

Just click ok, and voila it’s straight!

Using the measure tool to straighten an horizon takes out the guess work and speeds things up a little.

You still have to use the crop tool to get rid of the white space though…

after rotate

after rotate

I chose a very bad example of a wonky horizon to exaggerate the fix that was needed. So you could easily see what the measure tool can do.

And when I open an image in Photoshop, checking the horizon is straight is the first job I do. And fix it if necessary!

You can see the final image at the top of this post.

Do you use the measure tool to straighten an horizon? Any questions? Let me know in the comments below…



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