Cropping Digital Photos Into Shape

Did you know that in many cases digital photos are cropped by the time they reach paper? If you have never "cropped" your photos manually, you may not be aware that it is happening.

What is cropping?

Cropping is the process of trimming portions of the digital image so it fits in the shape of the paper. Let's say we have a 5" x 7" photo. The problem is, the frame we want to display is 4" x 6". One of our choices is to take scissors and carefully trim away the least important edges of the photo until it fits into the 4" x 6" frame. What we have accomplished is "cropping".

In the world of digital photography, cropping is performed with software. When the photo is comprised of bits of data, there is no need to crop for size alone—the software and printing process can stretch the image to fit. We do, however, have to crop digital images to fit the paper's shape.

A more detailed look

Let's look at an example. My Canon camera has a sensor size of 1536 x 2048 pixels. Dividing these numbers by the highest common denominator of 512, we get an image shape of 3 x 4.

How many print sizes do you think fit this shape? Not many. If we want 4" x 6" prints, the shape of the 3 x 4 digital image will not fit. It is possible to stretch the image into the 4 x 6 shape using software, but this will distort the image, which we don't want.

Our only option is to crop the 3 x 4 image into the 4 x 6 shape. If you are thinking, "I never had to crop my images and they always looked fine," then chances are the cropping was done for you automatically. Who would do such a thing behind your back?

Don't be alarmed, cropping was always done on our behalf, even with film photos. When we drop off our digital photos at a lab to have them developed, or insert them into our printer, the images are loaded into the computer system and are automatically cropped. How does the computer know which sections are OK to crop and which ones are not? It doesn't. When the decision is left to the machine, it will trim an equal amount from two edges.

Have you ever received a photo from the lab and something important near the edge was cut off, but when you saw it on the computer screen it was there? That is a result of automated cropping.

Do your own cropping for maximum control

Under most circumstances automatic cropping produces good results with our snapshots. In cases where we want to control precisely where the image is trimmed, we need to take the cropping under our own control.

Cropping can be accomplished in several places such as your photo editing or printing software, online developing services, or the kiosk machine available at many local labs. I find that the best place to crop your photos is on your own computer using the software you are most familiar with. If you have never used this feature of your photo editing software, I urge you to learn how to use it. The other two cropping methods are typically more time consuming. You may also be rushed during the delicate cropping procedure if a line forms behind you at a kiosk machine.