Articles of Interest

Crooked Horizons in Your Photos? - Here is a Five Minute Digital Fix
Gary Wilkinson
1798

Remember the good old photography days?

Film camera in hand, you would see that perfect landscape, seascape or sunset and shoot off several shots.

Perhaps a couple of weeks later, once you had returned home and finally finished that 24 or 36 exposure film, it was off to the photo-lab to get the film processed.

You eagerly open the packet of photographs, looking for that superb seascape you took, knowing that it would almost certainly be taken up by National Geographic for their monthly magazine spread.

What do you find?

A not too bad photo, but the seascape horizon is crooked, here's your excuse, I hear you say.. “Well when I took the shot I was standing on the side of a sand dune and quickly trying to get that perfect shot while the little sailboat was still in view”.

Does this sound familiar to all you budding Adam Ansels and/or Lord Snowdons?

The photo is relegated back to the packet never again to see the light of day.

I had many of those packets of not so perfect photos until the digital photography age arrived.

The Digital Darkroom has arrived

The advent of the digital camera and in fact, before that, computerized image manipulation software such as Adobe Photoshop has completely revolutionized the way we can now resurrect a stunning image from what at face value might have appeared to be just one of those snapshots to be relegated to the shoebox under the stairs.

What I'm going to show you in this article is just one method of taking a mundane snapshot and producing a great shot in as little as five minutes.

The example I'm going to use, is one that I have seen so many times, and have already mentioned above, namely, shots that have crooked horizons, whether this be a landscape, seascape, sunset or whatever.

The source of the image may have come from a scanned negative, scanned print or digital camera image all converted to an image format (most probably .JPG pronounced “jaypeg”) that can be opened in your image manipulation software.

Correcting a crooked horizon

The human eye is remarkably perceptive at picking out features in a photograph that are made up of essentially straight lines and that those lines are not parallel, either horizontally or vertically, with the overall print itself.

These straight lines may well be the horizon, but they may also be an object in your photo that has straight lines such as buildings or walls etc...

I will be using Adobe Photoshop CS, but almost all other image manipulation software packages have similar tools so the method described should be repeatable with your own software package.

The method used will employ a little known relationship between two Photoshop functions, the Measure tool and the Rotate Canvas command.

Step – 1
Open up your image in your image editor (in our case Photoshop) and select the Measure tool which if not visible on the Photoshop toolbar can be found by hovering your mouse over the Eyedropper tool and “left clicking”.

Watch the other options window “fly-out” and select the Measure tool.

Step – 2
Interestingly enough, we are not actually going to measure anything in the real sense of the word, nor use the Measure tool as it is usually used (i.e. measuring the distance between two points within the photograph).

With the Measure tool active, “left click” and “hold” on a spot on the left hand side of the photo (remember our example is a seascape) where the horizon meets the sea.

While still “holding down” the left mouse button, drag to the right hand side of the photo and find a corresponding point where the horizon meets the sea and then release the mouse button.

What happened? .. Well you will see that a white line has been drawn on top of the photo with what looks like little ”+” anchors at each end. The line is parallel with our crooked horizon.

Step – 3
Now the marvel begins!! Select the Image->Rotate Canvas->Arbitrary … command and the Rotate Canvas pop-up window will appear.

What you will notice (in the case of Photoshop anyway) is that it has ”pre-filled” the pop-up rotate options with the exact rotation information to correct the crooked horizon, 1.5 degrees counter-clockwise in our example on our web-site. Click OK and see what happens ..

The photo has been magically rotated the right amount to correct the crooked horizon!

Step – 4
All that is required now is to do a tight “crop” on the overall photograph and save it.

And there you have it!!Less than five minutes of digital image manipulation to take that mundane snapshot into a photograph that is very pleasing to the eye.

If you find the steps taking are a little hard to understand in this text based article, you can click on the link at the end of this article to see the same method explained on our website with the aid of example graphical images.