InDesign seems to offer unlimited design and production potential. But transferring designs into printed material may raise unforeseen problems. Most printers require the industry resolution standard of 300 ppi. PPI stands for “pixels per inch” and affects the print size and quality of your images. But if you do not have images saved at the correct ppi, or if you don’t have the time and resources to resize all your images, you can raise the ppi using InDesign without opening each image in Photoshop. Writer Bio

How to Raise an Effective PPI in InDesign - 20