Considerations When Enlarging Images: DPI, Pixelation, and Resolution

There are many instances where you may need to enlarge an image, be it a web image that you need to print for a project or a low quality digital photograph that you would like printed onto canvas or photographic paper for display purposes. There are many problems that are encountered while trying to enlarge an image. I’ll explain some of them here, as well as an explanation of the key terms that you need to understand before enlarging an image.

enlarging images

“mayis” captured by abeer

1. DPI

DPI (or dots per inch) is a measurement that is used to show either:

  • The amount of individual dots that make up 1 inch of an image. This measurement shows the total amount of dots that make up 1 inch of an image when displayed on screen. Most images found on the Internet today are displayed at 72 DPI. The minimum DPI necessary to produce a good quality print is around 150 DPI. This is where problems start when it comes to printing these images. Always check the DPI of the image you wish to print using photo editing software to ensure that the DPI is over 150. Any lower than this will result in poor image quality when printed.
  • The amount of individual dots of the ink used to print 1 inch of an image. This measurement shows us how many droplets of ink are used to make up 1 inch of an image when printed. This measurement is very important when it comes to printing a photo on canvas or other media. Regardless of the resolution or DPI of an image, if the printing equipment being used does not prints at a high level of DPI, (at least 300 DPI) then even the greatest quality image will appear blurry with a huge loss of detail and clarity. Always check that the company you choose to print your photo on canvas or photographic paper will be printing your image at the least 300 DPI.

2. Pixelation

Pixelation is a problem that is caused by increasing the size of a bitmap (an image made up by pixels such as JPEG files) to such a degree that the individual pixels become visible to the naked eye. There are ways to reduce pixelation using modern photo editing software such as Photoshop. There are methods that can be used to minimize the impact of pixelation.

3. Resolution

The resolution of an image is the amount of individual pixels that put together that image. The higher the amount of pixels, the less each pixel is stretched when the image is enlarged. The resolution of an image is the most important factor when thinking about enlarging an image. The higher the resolution of the image, the less pixelation that will occur and the better the image quality will be when printed.

So what is the best way to reduce pixelation when printing an image?

When you’re thinking of printing a digital photograph on a larger scale, whether ordering a photo on canvas or printing an image onto photographic paper yourself for display purposes, the best way to avoid pixelation altogether is to select an image that is high in resolution. With digital cameras now commonly available, taking photographs at a minimum of 5 megapixels, taking high-quality photos that can be transferred onto canvas is now even easier. If you have no choice but to use a poor quality photograph, always speak to a professional first to see what kind of result you can expect to see when your image is printed at a large scale. Many photo on canvas sellers specialize in editing and enlarging photographs and they will inform you of any issues before sending your photo to print.

Canvas prints
Canvas prints are by far the best choice when printing images at a large scale. Even at low resolution, photographs can remain crisp and clear when printed onto canvas.

About the Author:
If you would like some of your favorite photographs enlarged professionally and printed onto canvas, then visit Canvasking. If you’re looking for a high quality photo to canvas print or would like to know more about photo on canvas prints in general, please click the links in blue for more details.

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5 responses to “Considerations When Enlarging Images: DPI, Pixelation, and Resolution”

  1. David Thiel says:

    This article is full of totally incorrect information. DPI is an entirely irrelevant concept when working on the internet, and the concept that “the web is 72 dpi” is a holdover from the early nineties when graphic designers were holding rulers up to their screens. (Case in point, an iPhone 4 is approximately 330 dpi — until you pinch or zoom).

    Here’s an experiment for you: open an image in Photoshop. Click “Save for Web and Devices.” Now try to find the DPI setting on that screen. (There isn’t one!)

    • David Thiel says:

      BTW… the dpi example above is just one of the incorrect items in this article… even the implied definition of “resolution” here is incorrect.

  2. John Taber says:

    I have a very good teacher of Photoshop and he is a strong beliver that you should only enlarge a picture if it’s your only option. And then he says don’t.

  3. D McGee says:

    Do you think that for readers sake, and, to be correct you could use ppi instead of dpi? PPI refers to the pixel count in an image (pixels per inch). DPI refers to printing. To figure out how many ppi’s you need for your printer, you divide the dpi by 3 = # of pixel per inch needed to make a good print. i.e. A 720 dpi printer needs 240 ppi to make a print – without the printer’s software interpolating the file or throwing away pixels. This type of tutorial confuses newbees to no end and I hesitate to mention this site as a good resource for my class in Digital Photography.

  4. Ian Cooper says:

    “The minimum DPI necessary to produce a good quality print is around 150 DPI.”

    Absolute nonsense. Image quality depends on lots of things – one of them is the DPI, but if the closest you’re going to be viewing the image from is 10ft away, you can easily print at a lower DPI and the image will look fine. If, on the other hand, you’re going to be viewing the image from closer than 3ft away, 150DPI may not be high enough. The idea that there’s one set threshold for printing is utter nonsense.

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