It’s quite common for photos to be cropped when printing. This is because the aspect ratio of the picture taken is not the same as the paper that it’s being printed on.
Digital cameras typically take photos with an aspect ratio of either 4:3 or 3:2. These values describe the relationship between the width and height of the photo. Most compact cameras have an aspect ratio of 4:3, whilst most dSLR cameras have a ratio of 3:2. Some cameras also offer other optional aspect ratios, although they may simply describe them as “wide” or “panoramic”, which often refers to a ratio of 16:9, common in HD video recording.
As an example, an image with a 4:3 aspect ratio could be measured in pixels as 400 x 300, 800 x 600 or 2000 x 1500. All of these sizes have the same width to height relationship.
Looking similarly at the sizes of images with a 3:2 ratio, you could have 300 x 200 pixels, 720 x 480 pixels or 2000 x 1333 pixels. Again, in each example, the relationship between the width and height are the same.
|4:3 aspect ratio||3:2 aspect ratio|
In the above illustration you will see that both images have the same height (165 pixels) but the width is different. The 4:3 image is 220 pixels wide whilst the 3:2 image is 248 pixels wide.
A square image would have an aspect ratio of 1:1. The height and width are both the same, therefore the proportions of the two sides are equal.
Photographic prints however are usually stated in physical sizes, such as 6×4″, 7×5″ and 10×8″. Only the 6×4″ print has an aspect ratio that matches that of a camera, specifically the 3:2 of a dSLR. An enlargement printed on 10×8″ actually has an aspect ratio of 5:4. Wherever the aspect ratio of a print is different from that of the camera, some of the image gets lost – it disappears beyond the top or sides of the print.
Using our 4:3 aspect picture as an example, you will see that if we create a 10×8″ print from it, we will lose a little of the picture off the edges of the print. This would be even more pronounced if we were to use the 3:2 aspect photo taken by a dSLR. If we were to print a 7×5″ picture we would lose part of the top and bottom on the image. Regardless of the aspect ratio of the original photo, most standard print sizes will result in cropping.
Some online print labs offer dSLR friendly print sizes such as 7½x5″, 9×6″ and 12×8″. All of these sizes have an aspect ratio of 3:2 so none of the picture is lost. However, it can be difficult to find frames in these sizes.
The best way to deal with this issue is to allow space around your subject when composing your shots. In other words, don’t get too close. This will give you room to crop your photos so that nothing important is lost.
You can crop your photos using photo editing software such as Photoshop or Picasa. These will allow you to select a print size and create a crop window with the correct proportions. Alternatively, online photo labs often provide the ability to control how a picture is cropped.