It’s very easy to accidentally take photos on a slight slant so that horizons or buildings aren’t quite level, and straightening a photo is a very common photo fixing task.
Sometimes it’s useful to crop photos too, to get rid of unwanted objects around the edge of the frame or to get photos ready for online display or printing at specific paper sizes.
Very often your photo editing software will be able to straighten and crop images at the same time, but there are still times you might want to treat them as two separate tasks.
This is a basic and necessary adjustment that simply fixes a flaw in the photo and it’s something you will want to do ahead of any creative editing treatments.
If a picture is taken on a slant, it’s easy to fix. Some programs let you drag outside the edge of a photo to rotate it, and some provide a horizontal line gadget that you position over on object that should be level – like a horizon line – and the software rotates the image so that it is level.
You don’t always use a horizontal line to straighten a photo. Sometimes it’s a vertical object, like a tall building, that needs to be straightened.
Usually, when the software’s Straighten tool is active, you will see a grid overlay on the image to give you a visual guide to when it’s truly level.
Straightening a photo means rotating it, even if it’s only by a degree or two, so this leaves diagonal ‘wedges’ along the edges. Usually, the software will crop these off automatically, but you may need to do it manually.
There are two main reasons for cropping a photo:
- To get rid of unwanted objects around the edge of the frame which are spoiling the photo, or just to improve the composition generally.
- To make a version of the photo to fit different print or screen sizes for sharing or display. This is done for practical reasons rather than creative ones, and because you probably don’t know ahead of time what crop proportions you will need, it’s best to leave this kind of cropping until immediately before you share a photo. This ties in with image aspect ratios and why cropping is the last thing you should do.
You crop photos using a ‘crop marquee’. This is a rectangular box that encloses the area you want to keep. You can usually drag on the corners of the crop marquee to change the height and the width at the same time, or drag on the top, bottom or side edges to change only the width or the height.
Your software will also have crop aspect ratio options, where you can opt to keep the photo’s original aspect ratio, choose one of a number of common aspect ratios, or use a ‘freeform’ or ‘custom’ crop where you can change the crop marquee’s proportions without restriction.
If you choose a specific aspect ratio, the crop marquee will keep those proportions regardless of whether you drag a corner handle or an edge handle.
Cropping and straightening photos at the same time
It’s common now for software to let you rotate the crop marquee as well as resizing it, so it’s easy to crop a photo and straighten it at the same time. This can save some time if you need to crop out parts of the picture too, but keep in mind the advice above about when to crop photos and why.
Generally, a straighten tool will also crop the straightened image in just the same way as rotating the crop marquee, so you end up with the same result whatever method you use.