Image Resolution: A Guide

High and Low Image ResolutionWhen creating prints and other large graphics for customers, it is important that the image has a high enough resolution to print crisply and cleanly. We understand that this can be confusing to some customers, and is not always easy to explain. Here we will cover the basics of image resolution and why you can’t always just grab a picture you like off the web.

What is image resolution?

Resolution is a measurement of image detail. Increasing resolution will also increase detail, while making the image dimensions smaller. The reverse of this is also true, getting less detail when decreasing resolution, thus giving an image with larger dimensions.

Web versus Print

First of all, there is a difference between web resolution (as viewed on your computer screen) and print resolution. Web resolution is measured in pixels per inch (PPI), with an ideal resolution of 72ppi and print resolution is measured in dots per inch (DPI), with an ideal resolution of 300dpi for materials intended to be viewed up close.

For your reference, here is a table of the acceptable and optimum resolutions for various types of projects:

Output Device Optimum Acceptable Resolution
Desktop color inkjet printers 300 dpi 180 dpi
Large-format inkjet printers 150 dpi 120 dpi
Professional photo lab printers 300 dpi 200 dpi
Desktop laser printers (black and white) 170 dpi 100 dpi
Magazine quality — offset press 300 dpi 225 dpi
Newspapers 250 dpi 200 dpi
Screen images (Web, slide shows, video) 72 ppi 72 ppi

The Impact of Low Resolution Images

So, you’ve found the perfect image for your project, but the resolution is lower than suggested. What is the harm in just using it anyway? Well, beyond having a less-than-professional appearance, the image will have some telltale signs of low quality.

  • There will be a great loss of sharpness, giving it a blurry appearance.
  • The image will appear pixelated, with the individual pixels apparent to the naked eye.
  • Straight lines will have what is referred to as a ‘staircasing’ effect.

All in all, resolution can be confusing, but it is important in getting a professional, high quality print. As a general rule, always shoot for the highest resolution available. If you have questions about your image and if it will work for your project, give us a call at 651 633-2233. At Signsational Graphics, we are happy to answer your questions and work with you to produce exactly what you have in mind. Let’s get started on your next big business sign or graphics project today!