Printing Terminology: What is DPI?

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What does DPI stand for?

DPI stands for "dots per inch." It is a measure of an image's resolution. The more dots per inch, the higher the resolution. An image with high resolution has more visual clarity and detail than an image with low resolution (see image comparison below).

The meaning of DPI…

Now that you know DPI stands for "dots per inch", you are probably still wondering what the term "dots" means in the phrase "dots per inch." In printing, the "dots" refer to the miniscule ink dots that are applied by commercial printing presses.

When printing in full color, tiny dots of four ink colors - Cyan, Magenta, Yellow, and Black - overlap each other on the paper to form many different shades and hues.

Known collectively as CMYK printing, these four inks can combine to create around 16,000 colors.

Related Article: What is CMYK?

Even though the colorful images we see in brochures, magazines, comic books, and other printed pieces appear to be continuous sections of solid colors, the truth is these images are actually a collection of tiny ink dots on the paper. You can see these individual CMYK ink dots under heavy magnification.

High Resolution is the Industry Standard

In the printing industry, the threshold for high resolution images is 300 dots per inch. Hence, commercial printing presses output ink at 300 DPI to produce images that have clear and sharp details.

By the way, DPI refers to the number of dots per linear inch, not dots per square inch. For example, an image that is 100 DPI will actually have 10,000 dots per square inch (100 x 100). An image that is 300 DPI will have 90,000 dots per square inch (300 x 300).

Needless to say, image files with 300 DPI (90,000 dots per square inch) will contain much more detailed information about shapes and colors than 100 DPI images (10,000 dots per square inch).

This is why commercial printing companies request artwork and images to be submitted at a resolution of 300 DPI. Anything less will diminish quality and produce a result that is less than optimal. High-resolution printing is especially important for marketing and promotional materials because low-resolution images can reflect poorly on brand image.

What if I submit images with a resolution higher or lower than 300 DPI?

Following the industry standard of 300 DPI is recommended. Here's why...

Submitting images with a resolution higher than 300 DPI won't produce better results because most commercial printing presses aren't able to accurately reproduce resolutions higher than 300 DPI.

Also, files submitted for color printing are often very large, especially files for multi-page documents. Submitting images with a resolution greater than 300 DPI can increase the file size exponentially, thus affecting storage capacity as well as processing time for transferring the files.

Regarding the submission of images with a resolution below 300 DPI, these will not exhibit the best clarity when printed. For example, most images displayed on the Internet are 72 pixels per inch, which is low resolution. This is okay for a website because it decreases the file size and allows images to load faster in a browser. Web images also require less storage space on a web server.

However, low-resolution web images yield poor results when used for printed output. This is because there is not enough detail contained within the file to allow the colors to transition smoothly. This causes web images to appear blurry and jagged when printed.

An exception to the 300 DPI rule is very large printed displays, like billboards or tradeshow backdrops. Oversized prints like these often require a resolution less than 300 DPI. The lower resolution keeps the file size from becoming ridiculously huge. Also, because these sizeable images are viewed from a distance, our brains will actually fill in the missing detail to allow our eyes to see the images properly.

The success of any print project hinges on the concepts of DPI and Resolution. High-quality printing just isn't possible without high resolution. Hopefully this article has provided a better understanding of Resolution and the importance of DPI when printing.

Whenever a need for custom printing arises, be sure to get in touch with Color Vision. We offer both offset and digital printing services, so we can assist with just about any print project you may have. You may also be interested to know that Color Vision has been producing quality printing since 1984.

If you have a current print project and would like a quote, you can submit our quick Quote Request form by clicking here. Or, we can be reached by phone at 800-543-6299. We hope you will give us the opportunity to assist with your next printing project!