Photo Enlargement Printing: Maximizing Print Size

Photo enlargement printing is an easy and fun way to display and enjoy your photos. A common mistake made by people in printing photo enlargements is the tendency to exceed the size capacity of their image. The result is a stretched image creating a blurry photo enlargement print. This article will help you avoid common mistakes teach you to create excellent photo enlargement prints.

In order to maximize printing size, one must first understand the concept of dots per inch (DPI). A printing machine will place dots of ink onto paper to create an image and the quality of the image is determined by how many dots can be placed in a given amount of area. “Dots per inch” is the number of printed dots in a linear inch. To print photo enlargement, it is recommended that you do not reduce the number of dots per inch beyond 100 dpi. Professional photographers prefer to print their work at about 300 dots per inch, but the average point and click digital camera user would be satisfied with a print of 150 dpi. For the sake of this article, we will equate the pixels in a camera to a dot in printing and use the two terms interchangeably.

Most digital cameras that can be purchased in today’s retail electronics stores will produce between 6 and 12 megapixels. For demonstration purposes, we will choose 8 megapixels as our guideline. A standard 8 megapixel camera will produce a digital image that has the dimensions of 3456 x 2304 pixels (7,962,624 square pixels) at an aspect ratio of 3:2. (Aspect ratio is the ratio of the width of the image compared to the height of the image.) To calculate the maximum print size of this digital photo at 150 pixels per inch, we would divide the dimensions by 150 pixels.

Example:

3456 pixels/150pixels = 23

2304 pixels/150pixels=15.4

Using the example of an 8 megapixel camera, we see that 23x15.4” inches would be our maximum print size at 150 DPI.

However, it is not always necessary to maintain the photo quality printing requirement of 150 DPI. If your photo enlargement print is being viewed from several feet away, we are able to drop the DPI lower. This is because the human eye begins to blur the dots as viewing distance grows. We experience this effect on a daily basis as we drive. For example, billboards are printed at much lower resolution, because of the great distance at which they are viewed. It is not uncommon for billboard printers to print their images at 10 or 20 DPI! If your print is hanging high over a mantle or on a high wall in a room with vaulted ceilings, there is no reason to print at high resolutions. From this distance, even 100 DPI would create a stunning image. Use the chart below as a reference when calculating image DPI and distance of viewing.

Under 2’ feet distance = 300 PPI

2’ to 3’ feet distance= 200 PPI

3’ to 5’ feet distance = 125 PPI

5' to 10' feet distance = 100 PPI

Always consider these key factors in photo enlargement printing: number of megapixels your camera can create, size of print you wish to create and the expected viewing distance. Knowing these factors will help you calculate the maximum size of your print while maintaining excellent photo quality.