The Photo Workshop, Philadelphia

In digital photography, it’s hard to go very far without hearing the word, resolution. But what does it mean and how will it affect you and your images?

As you know, your digital images are made up of pixels. Resolution tells your output device (printer, monitor, etc.) how many pixels per inch (ppi) to use for your image. Sounds simple enough. But it can quickly get out of hand for the novice.

Monitors are low resolution. They only require 72 ppi to make your image look good on the screen. As a result, almost everything looks good on your monitor. Yes, you can tell when the image is out of focus but it’s basically going to be acceptable on the screen.

Printers, on the other hand, require at least twice as many ppi as monitors. Your home inkjet printer can make very nice looking enlargements using only 150 ppi. But your professional lab needs 300 ppi. This is why photos that have been resized for email often look so crummy when you have them printed anywhere but your home printer.

How can you check the resolution before using your digital image? If you have Photoshop Elements at home, open up the image and go to Image > Resize > Image Size. Here it will tell you have many pixels you have in the Width and Height as well as the resolution.

The resolution is 300 ppi

This will make a print slightly larger than 5×7. Your lab may even be able to double the size to 10×14 if necessary. But above that size, you’ll want to think twice.

Here’s the same image but I resized it to email. The resolution is now 72. Take a look at the information below. You can also see that the number of pixels has diminished.

The resolution is 72 ppi

If I were to change that 72 back to 300, the print size would be significantly smaller than the original 5×7. See below.

Email resolution changed to print resolution

I wouldn’t recommend printing this file at any size. Well, maybe you could get away with a wallet.

Here’s what you need to know… If you’re printing, resolution needs to be 300 ppi at the size you want to print (up to about 16×20). For larger prints, the resolution should still be 300 but it can be half the final size. That means a 20×30 poster could be prepared at 10×15 with a resolution of 300 ppi.

If you’re emailing the photo, the resolution should be 72 ppi and your pixel dimension will ideally be 600 or less on the longest side. You can crop your photo and specify the number of pixels and the resolution for this step.