Less than 2 MP
Pixels Per Inch (PPI): A measurement of image resolution that defines the size at which an image will print Dots Per Inch (DPI): A measurement of printer resolution that defines how many dots of ink are placed on the page when the image is printed Megapixels (MP): One million pixels, though this number is often rounded when describing digital camera resolution
Suitable only for on-screen viewing and wallet-size prints
2 MP = 1600 x 1200 pixels
High quality: 4 x 6 inches, 5 x 7 inches
Acceptable quality: 8 x 10 inches
3 MP = 2048 x 1536 pixels
High quality: 8 x 10 inches
Acceptable quality: 10 x 13 inches
4 MP = 2272 x 1704 pixels
High quality: 9 x 12 inches
Acceptable quality: 12 x 16 inches
5 MP = 2592 x 1944 pixels
High quality: 10 x 13 inches
Acceptable quality: 13 x 19 inches
Megapixel Madness
Digital camera manufacturers would have all customers believe that a higher megapixel count is always better; however, as you can see from the chart above unless you have a large-format inkjet printer, anything greater than 3 MP is more than most people will ever need. Sometimes, though, more megapixels come in handy. They can give amateur photographers the freedom to crop more aggressively when they can’t get as close to a subject as they’d like. The tradeoff is larger files that require more space in your camera’s memory and more storage space on your computer. The cost of additional storage is likely worthwhile, though, especially for those times when you capture that priceless photo and want to print it in a large format for framing.
A Final Note
The most critical thing to understand is that you shouldn’t increase the PPI value of a photo by increasing image size and resolution values in Photoshop or other image-processing apps. When you do so, the final file size and image dimensions increase dramatically, and the color information in those new pixels is only a “best guess” on the part of the computer. Bottom line, if an image has a resolution of 200 PPI or less, it just shouldn’t ever hit a press.
