Why is DPI important when printing?
First things first… let’s define exactly what is DPI?
DPI stands for Dots Per Inch. You may have also heard others mention phrases like Pixels Per Inch (or PPI) when referring to the overall resolution of an image. The idea of DPI and PPI are often confused as being the same thing. However; when it comes to the print world, DPI makes the world of difference to the overall quality/sharpness of your printed image.
DPI will determine how many different dots of colour a printer is using to make up a pixel of information, whereas PPI is a term that is mainly used in relation to how much an image can be blown up or shrunk when displayed on a monitor or a television screen.
Raise your hand if you have ever grabbed a picture from a random website, tried to copy and paste it into your own document, then sent it to get printed. I can only imagine that pretty much everyone has done this in the past at least once. In some of these cases, if the image is not altered in size, the printed image will come out just fine. Nothing spectacular, but well enough to get the job done.
However; if you have attempted to increase its size for your document, the image will appear very blocky/pixelated. This is because most images that are taken from the internet are purposely manipulated to have a lower DPI; in an effort to decrease the size of the file and allow it to load much faster on the webpage. A photograph or image may have originally been saved at 300 DPI or higher, but websites are forced to lower this to 72 DPI or 150 DPI. This is why printed images from a website are of a considerable lower quality and should be used with caution when doing commercial printing, or formal projects where high-quality is key.
Check out the examples below to see how one image can look at 72 DPI compared to one that is 300 DPI.
Example: Photo at 72 DPI
Example: Photo at 300 DPI
There are many of great online sources to find high-quality images that are allowed to be used in other people’s printing projects. In this case, there is typically several versions of the same image that allow for high or lower resolutions or DPI. Be sure to check out what options would best suit your image when using these files.
I hope this helps with understanding why DPI is so important when getting your projects professionally printed!