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Low Resolution and Pixilated Images
By Joan Whetzel
Very often we hear the terms “high resolution” and “low resolution” tossed about when referring to visual media (photos, TV, movies), but it’s not often clear what is meant by the terms. When uploading digital photos to our computer, and see that the look really clear and sharp, we understand, at least on some level, that they are “high resolution.” The problem is that, just because a picture looks good on paper or on your computer screen, doesn’t mean it will look good when it’s blown up larger than life.
In digital photography, the images are made up of a bunch of colored, square dots called pixels. The number of pixels in the image depends on the resolution, called DPI (dots per linear inch). An image with a DPI of 72 has 72 pixels per linear inch, and an image that is 72DPI x 72DPI ahs 5,180 pixels per square inch. When the image has enough pixels per square inch to make a small, fine pattern, the pixels meld together making them look, to the human eye, like they’re contiguous or connected.
As the image is enlarged, the number of pixels are not increased, but the size of the pixels and the spaces between them are enlarged. The individual pixels will no longer appear joined together and the images become “pixilated.” Pixilation makes the image look chunky or blurry, and kind of jagged around the edges.
The problem with changing the size of the digital image, is that the number of pixels has not changed, they’ve only been made bigger. So a “high resolution” picture that looks clear and sharp when it’s small becomes “low resolution” when it becomes larger because the holes in the digital information have not been filled in.
This photo of the hot air balloon was taken from some distance away. The photo in its original, “high resolution” form is sharp and the edges are clearly defined. But cropping the image to include only the balloon, and then enlarging that image, clearly shows how quickly the photo becomes “low resolution” and pixilated. The edges of the balloon are no longer smooth and round but make the balloon look as if it was made up of a bunch blocks piled up together.
For a large digital image to be clear and sharp it needs more pixels per square inch. In order to get higher pixel count, the photographer either needs buy a camera with multiple pixel count selections or that takes those images with a higher pixel count, or the photographer needs to increase the pixel count in the editing process using a program like Photoshop.
Using photography programs like Photoshop, the pixels can, in effect be doubled so that a picture can be enlarged – to a point – without lowering the resolution and without producing pixilated photos. Beyond that doubling up, though, it isn’t possible to add more pixels per square inch because the images would take far too much space to store and a too much time to upload to the computer.
Another problem also occurs when trying to enlarge a picture that is grainy or muddy. Just because the image was taken with a high resolution camera (one with a high pixel count) doesn’t mean it will become clearer once the image is enlarged. A blurry picture will only get more blurry the bigger it gets. Photoshop and other similar programs will not help.
Pinnacle Displays. "Low" Vs "High" Resolution (dpi) -What Does It Mean?
Contemporary Communications. High Resolution Images Vs. Low Resolution Images: A Short Primer for Beginners.