{"id":69748,"date":"2020-10-09T10:24:11","date_gmt":"2020-10-09T09:24:11","guid":{"rendered":"https:\/\/www.solopress.com\/blog\/?p=69748"},"modified":"2022-04-05T11:23:28","modified_gmt":"2022-04-05T10:23:28","slug":"what-is-dpi","status":"publish","type":"post","link":"https:\/\/www.solopress.com\/blog\/art-design\/what-is-dpi\/","title":{"rendered":"What is DPI?"},"content":{"rendered":"
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The concept of DPI is a relatively simple one in the worlds of design and print, but it gets confusing quickly once we start diving into the details. And DPI is all about the details!<\/p>\n

Essentially, DPI is a measurement that’s used to evaluate the level of detail that can be reproduced by a printer. The higher the DPI, the more information can be captured in print. A high DPI means the resulting print should have a higher resolution, appearing sharper and more detailed.<\/p>\n

That isn’t the whole story though. The quality of the image that emerges from the printer is a result of much more than the printer\u2019s DPI rating. Add to that the fact that DPI is often mistaken to mean \u201cdots per square<\/em> inch\u201d, or \u201cpixels per inch\u201d, and it is clear we have some explaining to do. Let us start at the beginning.<\/p>\n

What does DPI<\/strong> stand for?<\/strong><\/h2>\n

DPI stands for \u201cDots Per Inch\u201d and is used as a measure of the level of detail reproduced in an image or by a printer.<\/p>\n

The term \u201cdots\u201d refers to the dots of ink applied by a print device. Dots per inch refers to a measure of how many of those ink dots are applied along an inch-long line of the printed material, also known as \u2018dot density\u2019. It gives a good indication or the sharpness of detail that can be achieved by that print device.<\/p>\n

What is DPCM?<\/strong><\/h2>\n

DPI stands for \u201cDots Per Centimetre\u201d. As you might expect it is the metric equivalent of DPI. Despite the practicality of DPCM, it is not a widely adopted term and DPI remains the industry standard measurement for dot density.<\/p>\n

How does DPI affect resolution?<\/strong><\/h2>\n

Digital print is an optical illusion. For the print to be successful, we need to present a matrix of dots that’s fine enough to fool the human eye. Viewers must think they are seeing a representation of something they might see in real life. Something that consists of continuous lines and images, rather than a dotted pattern.<\/p>\n

To achieve that, certain conditions must be met. The density of dots, the size of the image, and distance from the observer must all be in the right range for our illusion to work. That’s where DPI comes in. It is a handy measurement for us to use when judging how finely we need to print so that our images to appear smooth and detailed in context.<\/p>\n

Is dot density measured over one dimension or two?<\/strong><\/h2>\n

DPI is sometimes presented as a single number like 1200dpi. Elsewhere, you might see the same measurement written as 1200 x 1200dpi.<\/p>\n

That’s because DPI for printing refers to the number of dots that appear along an inch-long line, not within a square inch area.<\/p>\n

1200 x 1200dpi is a more complete way of expressing dot density, as it is a measurement that refers to area. The two numbers together give us dots per square<\/em> inch. We need the horizontal and vertical measurements to make sense of the quantity and arrangement of dots within a 2D square.<\/p>\n

However, where the two values are the same, the number is often stated just once. 1200dpi becomes shorthand for 1200 x 1200dpi.<\/p>\n

But those two numbers are not always the same! Some inkjet devices may have a different DPI in the horizontal direction compared to the vertical. Where a print head moves across a page, the printer might apply more dots per inch across that axis. This is helpful in distributing and blending its limited number of inks more precisely to reproduce colours more accurately. Many high-end home and office desktop printers that boast \u2018photo quality\u2019 results, for example, might print at 5760 x 1440dpi, 4800 X 2400dpi, or 9600 x 2400dpi.<\/p>\n

So, to give a full story about the print density, a measurement of DPI in two dimensions should really be expressed as a pair of numbers.<\/p>\n

DPI vs PPI<\/strong><\/h2>\n

That’s all very well when it comes to printers, but doesn\u2019t DPI have something to do with digital graphic design and the size of image files?<\/p>\n

This is where the confusion comes in with a related but different concept called PPI, or \u201cPixels Per Inch.\u201d DPI is all about dots of ink, but electronic screens, image files, and digital camera sensors all work in pixels. DPI is how we measure the density of pixels, rather than ink dots.<\/p>\n

It doesn’t help that people often say DPI to refer to a digital image when what they really mean is PPI.<\/p>\n

Most designs that end up in print start life on a computer. If we want a high-resolution result in print, we need a high res digital image to start with. The problem with high-resolution digital imagery is that it involves a huge amount of information. This leads to large files that take up space, require a lot of processing power to manipulate, and are cumbersome to move around.<\/p>\n

So, the balancing act becomes how we accommodate image files that do not overburden our computers but still result in high-quality print.<\/p>\n

How \u2018big\u2019 does my digital image need to be?<\/strong><\/h2>\n

When you consider how \u2018big\u2019 your digital image is, you might be considering one of three attributes:<\/p>\n