Reso…what? Your Guide to Image Resolution

Whether it is for print or screen, image size and resolution is key. At least once a day I have to explain image size and resolution. Usually because the image the person provided is usually low resolution for print and I bring it to their attention. Hoping they would send an image that is high resolution for print. As a low resolution image would look blurry, grainy, and not sharp when printing. So, what is image resolution you’re asking? Basically, resolution is the quality of your image that you are using. As you increase the resolution of an image the quality is better and becomes sharper. There are three different ways to describe a digital image’s resolution that mean the same thing: pixel dimensions, DPI at a certain digital image size, and DPI at a certain output size.

Pixel dimensions – The total pixel dimensions of an image will tell you how many total pixels (dots) the image is made up of.

Digital Image Size – It is the size in inches of your digital image.

Print Size or Output: The size in inches of the print that you want to make from your digital file.

For print, I usually recommend images and graphics be at a 300 DPI. Now what is DPI? DPI is “dots per inch.” This number is calculated using your digital image’s pixel dimensions and digital image size. It is also how many physical dots of ink will it print in a full square inch. The higher the DPI, the more information there is, so you get more detail you can see and the image looks sharper. There is also the term “pixels per inch” which is the same as “dots per inch” or DPI. Pixels per inch are how many squares of colored light a screen fits in one square inch. Whether it is DPI or PPI this only comes into play for when the image is physically printed or put on the screen. When I say I need a photo that is 300 DPI it is referred to as a high resolution photo. A high resolution photo generally means a high PPI or DPI (usually 300 or greater) when printed. Even 200 DPI is good for print but I usually like asking for 300 DPI. DPI may seem confusing, but it can be very helpful when discussing photo, art, marketing etc…prints because a print with sufficient dots per inch (DPI) will appear sharp, not pixilated. Especially for print, make sure your image is as large as possible with the highest possible DPI. You can always scale down, but you can’t scale up.

Now for screens or the web, I recommend the resolution of an image or graphic be 72 DPI. Your computer screen shows the images on your computer at a web resolution of 72 DPI. Web graphics and online photos are normally created at 72 DPI. This low resolution is great for the web as you want images and graphics on the web to load fast. No one visiting a website is going to wait for an image to load if it takes too long if the image is too large on the web. Also you have pixels per inch which are how many squares of colored light a screen fits in one square inch.

All though for example, if you grab a logo off a website for a business and put that logo on a flyer you are going to print the logo will look blurry since that logo was sized for the web for 72 DPI as compared to using a 300 DPI high resolution logo. If you want a high resolution image of the logo it is best to get a high quality PDF or ideally an EPS format of the logo. PDF is Portable Document Format. EPS is Encapsulated Postscript Vector it is a nice vector format that can be sized easily without distortion. If you were given an EPS file of your logo whether for a business or organization make sure you keep it.

Designing for print, always make sure the graphics and images are high resolution usually 200 DPI or greater. Ideally use 300 DPI, using images that are high resolution will make sure that everything is sharp and clear when printed. For a website or on the screen, use a low resolution 72 DPI for fast loading. Your computer screen shows the images on your computer at a resolution of 72 DPI as well. Make sure your image is as large as possible with the highest possible DPI. You can always scale down, but you can’t scale up.