The Importance of Image Resolution in Creating High-Quality Print

The resolution of a digital image is measured using pixels, specifically the number of pixels per square inch (PPI). Printed images are measured using a similar standard known as dots per square inch (DPI), which quantifies the number of ink droplets a digital printer will apply to a sheet when printing an image file. 

While designers have to account for PPI and DPI when designing digital assets, DPI is more important for digital inkjet as it is a closer measurement of how images will be replicated on the page. DPI also helps designers account for the clarity and detail of an image as a larger DPI indicates more dots will be applied to print an image. 

Though the measurements can vary depending on the printer, most inkjet devices can produce images at 300 dpi. This means that every inch of the substrate contains 300 dots of ink, and 300 dpi is more or less the standard for designers and photographers in printing the highest quality images. 

“For higher-end jobs, some printers will request scanned or bitmap images over 300 dpi because the resolution of new inkjet presses may be more than two or even four times greater than 300 dpi,” write Gooding and Schilling. 

It’s important to note that the right image file resolution depends on a variety of factors, some of which include the size of the image and how much space it will take up on the printed page, and the combination of paper, ink, and printing device. 

That being said, Gooding and Schilling argue that there are a couple of best practices designers can implement when selecting or adjusting image resolution to create high-quality images that are not blurry, pixelated, or dull. 

“Although high resolution adds to the overall size of press-ready files, keeping the resolution of any photos or bitmap images consistent with press resolution is important if you need to reproduce them with the highest detail possible,” write Gooding and Schilling. 

Additionally, designers need to consider the resolution capacity of the inkjet device they’re printing on and adjust their design files accordingly. 

“Saving the bitmap image at, or very near, the resolution of the printer will allow the printer to convert pixels to dots without limiting the production resolution,” explain Gooding and Schilling. 

“This method is best for projects requiring top-quality production, like marketing collateral and direct mail, and not recommended for projects like customer communications, where speed and efficiency is more important than production quality.” 

Gooding and Schilling also stress the importance of collaboration with your print provider to ensure image resolution does not suffer when the printer receives and engages with your design files. 

Designers should make sure to save their design files the way in which they want them to be used, and a clear line of communication with your printer partner can reduce the chance that the resolution of your files is not downsampled in service of increasing print efficiency. 

While this is a good foundation for understanding the importance of image resolution in harnessing the print quality digital inkjet provides, there’s still much that designers need to know about how to create and finalize their design files for a streamlined production process.