INTRODUCTION

Is it possible to take the output from a six-megapixel digital SLR camera and enlarge it until it meets the file-size and quality standards of publishers for digital image submission?

This question is being discussed all over the Internet. A large number of people are using cameras in the six-megapixel range, and would like to sell their images to stock agencies, or submit them to magazines for publication. Most stock agencies require a minimum file size of 50 megabytes to accept a submission. But, a six-megapixel digital camera produces a file that can be converted to an 8-bit TIFF image of only about 17.5 megabytes, well below the “standard.” To find out if it is possible to enlarge (interpolate) images from 17.5 to 50+ megabytes, and still maintain quality, I decided to use a couple of easily available software programs.

As a test image I chose a low-contrast picture of three cute children standing by a dam. This is a handheld shot taken with a Nikon® D100 digital camera in RAW mode, and later converted to an 8-bit TIFF at 17.5 megabytes. I am showing the test image as a 600 pixel wide JPEG with 10% compression, and mild sharpening.

The image I cut out from the non-interpolated test image has no manipulation of any sort. The cut out from the interpolated image, being 50% larger, had to be reduced to show an apples to apples conversion. The red rectangle shows the part of the image I cut out for viewing of the interpolation methods. Here is the test image:

First, I used LizardTech® Genuine Fractals to do the enlargement (interpolation). In Figure 1 below, you will see two 300x350 pixel images. The one on the left is a cut out at 100% from the 8-bit TIFF image. The one on the right is the image after I used Genuine Fractals to enlarge it to 52 megabytes (175% setting at 300dpi), and then converted it to an 8-bit TIFF. Can you see any differences!