How to Change the PPI of Embedded Images in Illustrator

A pixel is a small, square colored dot that helps to make up a digital image.

PPI (Pixels Per Inch), is a unit of measurement used to refer to how many pixels, or dots, are located in an inch of an image. PPI is often confused with DPI (Dots Per Inch), which refers to how many dots are located in an inch of an image when printed. Because Adobe Illustrator is a vector-based program, it does not use PPI, except in the case of imported images and thus PPI has very minimal functionality in the program. However, despite the limitations with PPI, you can change an image's DPI, thus better preparing it for the web or printing.

Instructions

1. Open Adobe Illustrator and load a file with an embedded image.

2. Click on "File > Print" and select an "Adobe PDF," "Adobe Postscript File" or "PostScript Printer," from the "Printer" dropdown menu.

3. Click the "Output" option on the left of the print window and chose an LPI and PPI value from the "Printer Resolution" drop-down menu. LPI is used to describe screen frequency. Click "Save" or "Done."

Tips & Warnings

• Illustrator automatically adjusts the PPI of an image when you scale it. Thus, reducing an image in size by 50% multiplies the PPI of the image by 2.

• You can also change the PPI of an image in another program, such as Adobe Photoshop or InDesign, before importing it into Illustrator.

References

• Adobe: Change the Printer Resolution and Screen Frequency
• Avenza Systems: Finding Image Resolution in Adobe Illustrator