When considering what paper size you should print your photos on you should first consider what the print will be used for and what size will be useful for you. Hanging a digital print on the wall is different than placing it on your desk inside a tradition paper photo frame.
One you have decided the print size that best fits your needs you will need to figure out the quality of the digital print that you need. Quality of digital photo prints is usually expressed by one main number known as the dots per inch. The dots per inch also known as DPI represents the number of dots that are printed on every inch of paper print. In other words the dots per inch represent the density of the dots on the paper print.
The higher the dots per inch number the higher the quality of the print. So how many dots per inch is good enough? The answer depends on how the digital prints will be viewed. The closer a print is viewed from the higher the dots per inch density needed and vice versa. Since there is usually some correlation between the size of the print and the distance from which it is viewed there are some ballpark common dots per inch numbers that represent different digital prints quality.
The common agreement is that any dots per inch density higher than 300 represents a high quality digital print. Dots per inch density of 200 is still a good print. With very large digital prints that are viewed from a distance such as street billboards dots per inch of 75 is more than enough.
Dots per inch is not just an option that you can choose when placing your digital print order. If that was the case than why not always choose the best quality? The dots per inch is actually a number that can be calculated based on two parameters the original digital photo resolution and the digital print size. When taking digital photos the camera captures the photo by saving a long series of pixels. The number of pixels changes from one camera to another camera. For example a 2 mega pixels camera captures the digital photo over a serious of 2 million pixels.
When printing the printer basically takes the pixels in the original digital photo and prints them on a special photo paper. The printer can only use the pixels in the original digital photo. The dots per inch of any print is thus the total number of pixels in the original digital photo divided by the size of the digital print paper. In other words every digital camera has a maximum digital print size that it can support at high 300 dots per inch quality. Here are some pre calculated maximum digital prints sizes for a few common digital camera mega pixels figures.
