How to Understand DPI

Commercial Printing

DPI, or dots per inch, is a measurement of printed resolution. DPI is commonly, yet mistakenly, used when speaking of monitor, scanner and digital imaging resolution; these use pixels instead of dots. The more printed dots present on a medium, the higher the image and text quality. More ink is used to produce higher-resolution images. For everyday and draft printing, lower-resolution settings are used. Typical settings are 150 or 300 DPI. High-resolution settings start at 600 DPI.

Difficulty:

Easy

Instructions

1. Print output settings can be changed by adjusting the print preferences. For example, typical printer settings include fast draft, fast normal, normal, best and maximum DPI. The fast draft setting sets the print output to 300 DPI. Fast normal is also a 300 DPI setting. The normal setting is the default print setting with a 600 DPI output. The best setting also has a 600 DPI output and a high photo print resolution. The maximum DPI setting supports a 1200 DPI print output but requires a large amount of RAM memory and hard drive space, and the print time is very long.

2. Display resolutions are a little different. If your screen resolution is 96 DPI, the number of dots per square inch equals 9,216 (96 DPI x 96 DPI); a 100 DPI resolution equals 10,000 dots per square inch. Doubling the resolution quadruples the number of dots: for instance, a 200 DPI resolution produces 40,000 dots per inch.

3. DPI settings for scanners work in the same way as printer DPI settings: the higher the setting, the higher the resolution and image quality produced, and the more memory required to produce and store the image.

References

• What is DPI?
• Definition of DPI