Dpi
This is an abbreviation for “dots per inch”, a measurement of print image resolution and quality.
A larger number of dots allows for more detail, and therefore a higher resolution image. Printer resolution can range considerably depending on the price and use of the product. Some lower-end laser printers have a resolution of 300 x 300 dpi, which means they can print 300 dots per inch horizontally and 300 dots per inch vertically, or 90,000 dots per square inch. Most home laser printers will be at least 600 x 600 dpi, while professional quality laser printer will print at least 1200 dpi or 2400 dpi. Photo printers on the other hand, because they need to more faithfully reproduce an image, should be capable of printing at several-thousand dpi.
Frequently Asked Questions
How can I adjust the dpi of an image?
There may be times when it’s helpful to adjust the dpi of an image. For instance, when you scan a photograph, you can adjust the dpi to determine the quality of the digital image that is produced. The higher the dpi, the higher the quality, but also the larger the file size. Most scanning software will allow you to adjust the dpi so you can find the optimal balance between quality and size. When printing images, you may want to use a very high dpi to get the best image quality, or a low dpi to save on ink. Some printers will allow you to select a specific dpi from the Printing Properties menu, while others will give you a list of quality options, such as Economy, Fine, and Photo. Economy will use the lowest dpi, in order to minimize ink usage, while Photo will give you the highest dpi to better reproduce the original image.
How does dpi compare to pixels?
Dpi is used when referring to a printed image. That’s because printed images rely on placing ink “dots” directly on the page, where each dot contains a specific color. By overlaying dots of differing color inks, a printer can create a wide spectrum of colors. The higher the dpi, the more accurately the printer can reproduce specific colors.
Pixels are used to determine the quality of a digital image. Your computer monitor or mobile device’s screen has a specific number of pixels it can display on the screen. If an image has more pixels than this, it will compress the image to fit. If the image file has less pixels, it will spread each image pixel across a proportionate number of monitor pixels, stretching the image. The more an image is stretched, the lower the quality will appear. Like dpi, the more pixel data available, the more accurately the image can be reproduced.
While dpi and pixels have separate purposes, they do impact each other. The higher the pixel count in a digital image, the more specific color information a printer has to work with, making it possible to produce a higher-quality image (provided the dpi is set high enough).