Understanding File Resolution

pisel demonstration

What happens on the printed page when the resolution is wrong. The area on the left is soft and "jaggy". You can see this especially well on the closest wing.

But it looked good on my screen…

Just because something looks good on your computer screen doesn’t mean it’s good for print. Computer screens have a resolution of 72 ppi (pixels per inch, a measure of the density of pixels in a given space). Files fit to print need to be 300 ppi. If you take a picture off a website and try to put it on the printed page at the same size, it will look soft and “jaggy”.

A good rule of thumb is the size of the file. When open, an 8.5 x 11 picture should be around 24mb. If it’s significantly smaller than that, the file is suspect.

In one sense, it’s relative. That same 8.5 x 11 file when viewed at 72 ppi is nearly 48 inches high. It’s the same amount of pixels, just spread out more. And if it were to go in a print magazine, would print at the 8.5 x 11 size.