Digital Learning > Miscellaneous articles
Aspect Ratios and Cropping Considerations for
Digital Images
Cropping and Resizing Images (continued)
To demonstrate the importance of aspect ratio, The left hand image below is a scan of an original 1926 photo print, which measured 2.75" x 4.5" for an aspect ratio of 1.64. If our intent is to print it as an 8" x 10" enlargement, we would have to find a way to adjust the aspect ratio to 1.25, a fairly meaningful adjustment.
The middle image shows a crop off the top of the original image to maintain the full width of the image and to include the date at the bottom of the photo. Unfortunately, the only way to save the date is to lose the head. The right hand image shows a second manual crop to attain the 1.25 aspect ratio needed for an 8" x 10" enlargement while retaining the key elements of the image.
Tip / Hint:
If the aspect ratio of the original image is
greater than the aspect ratio of the planned print size, the
longer dimension will be cropped.
If the aspect ratio of the original image is
smaller than the aspect ratio of the planned print size, the
shorter dimension will be cropped.
You can quickly calculate the amount of image to be lost in a default
crop by comparing the aspect ratios. In our example above, an
aspect ratio of 1.25 is roughly 76% of 1.64, resulting in the need to
crop roughly 24% off the height of the first photo in order to print the
entire width.
Current versions of image editing software, including Photoshop Elements, include the ability to select an aspect ratio and then crop within an image to this ratio. This provides strong control over the cropping process, and allows you to manually crop to an optimal aspect ratio before uploading to an online printer or for another purpose.
Learning to manually crop your original digital or scanned images is also very useful in eliminating unwanted elements that have found their way into the image, and in re-composing an image to highlight certain elements.
Assuming the subject of an image is not tight to
the edges of an image, most default cropping will provide satisfactory
results. Most online printers also provide you some control over
the process by allowing you to opt for filler border strips instead of a
default crop. For example, If more than 20% of an image would be cropped by
default, Shutterfly.commakes the default assumption that you would prefer
to have the entire image printed with filler borders instead of a crop.
Tip / Hint:
If you are working with fairly common sizes of images and
prints, you can quickly inspect your image to make sure that no
important elements are close to edges. You can then feel confident that a
default crop will likely be successful.
If you are working with unusual aspect ratio images, or you have
important elements near the edges of the images, it is useful to assume
more control by cropping your images using image editing software such
as Adobe Photoshop Elements 7,
When you crop an image to adjust the composition or aspect ratio, keep in mind that you are cropping pixels. Once the image is cropped and saved, the image pixels outside the crop area are no longer available for future uses.
Tip / Hint: If you often crop your images, you may want to get in the habit of routinely capturing more pixels. Then, even if you crop aggressively, you will still have enough pixels for quality print enlargements. It is also a good habit to always use a copy of an original camera image or scan for your varied projects. This will prevent a situation where you may have cropped an image for one project, and then find that the remaining pixels are too few for another purpose.
