Image Resolution and Printing

There are a handful of topics related to art and design that have the ability to cause even more confusion the more you research them. Image Resolution – specifically DPI vs PPI – is often one of these confusing subjects. If you are looking to make your designs pop on Redbubble, here are some good lessons and best practices to learn from!

This goal when designing should always be to create high-resolution files. This directly refers to the sharpness and clarity of an image. Resolution can be measured in multiple ways: PPI and DPI.

Pixels Per Inch (PPI) refers digital images on screens and Dots Per Inch (DPI) refers to the density of ink dots used by printers when creating physical prints. Every printer has a different resolution it can handle, and depending on the process the resolution can be changed allowing for different sizes when printing. For example, you may have heard “300 DPI” mentioned when it comes to optimal printing resolutions. This isn’t entirely true, especially when dealing with how you view images on a screen. Check out the following example featuring work by Madkobra.

Each of the images below may look identical, yet they are quite different. All three files are 400×500 pixels and 152 kb in size. The one on the left is 300 DPI, the middle one is 72 DPI, and on the right 1 DPI.

When it comes to screen resolution, 400px wide is 400px wide no matter what the DPI/PPI is set at. This is why many have referred to worrying about DPI as pointless when it comes to sizing digital images, as what is truly important is the actual pixel dimensions.

Even though the examples above all have the same pixel dimensions, the PPI denotes different printing targets. The 300 DPI a target of 1.3 x 1.6 inches (the size of a small sticker), 72 DPI has a target of 5.5 x 6.9 inches (the front of a clock),  and the 1 DPI a target of 400 x 500 inches (the side of a house).

Depending on the viewing distance the DPI can be lower. This means an extremely large billboard is printed with a really low DPI. This is also one of the reasons why it’s still good to think about using PPI to allows for different size changes.

Another good reason to think about PPI: you don’t always have exact pixel dimensions to work with. To make your life easier, we give you a breakdown of the pixel dimensions for each product as recommended by the printers. If you’re ever commissioned to make a design that is going to be 16″ x 20″, it’s a good idea to aim for 300DPI just to be safe. You can always adjust to 150 DPI after it’s done.

There are so many different machines, processes, and calibrations to consider when printing. It’s best to take the recommendation of the printer as their goal is to print your work at an optimal resolution for the setup they have. If you’re given exact pixel dimensions and a target DPI/PPI, it’s typically done so for a reason based on a number of factors.

When creating new designs, make them with as many pixels as possible. It’s also a good idea to have a high resolution (200 DPI minimum, 300 DPI for good measure) and save this version as your master design file.

Keeping a master file will allow you to easily export the recommended size and resolution a printer needs. It’s always better to scale down in size rather than up, especially when you have a target size to to work with, and not exact pixel dimensions.

We hope this helped clear the murky water a bit! If you find this topic interesting we encourage you to hit the web and do some research. Just remember to bring some swimming gear and a flashlight.

Did you find the tutorial helpful? Please let us know in the comments below, and share any tips you might have.

(Banner image: Rainbow Factory by fabric8)