Is bigger really better ?

A recent discussion on a popular stock photography mailing list has prompted this posting about image quality. According to the mailing list a number of Stock Photography agencies are requiring the photographer to submit 50 Megabyte and 100 Megabyte files.

The average 35 mm transparency scan can produce excellent results at 20 MB. Anything above 20 MB is just scanning pieces of grain. The image quality does not improve only the file size gets bigger.

Popular DSLR cameras 6, 8 or even 10 Mega pixel cameras do not produce 100 Megabyte file images. To achieve this minimum requirement the photographer must interpolate the image in Photoshop or with some third party tool. In doing so the software spreads out the existing pixels and tries to fill in the blank areas with data based on the computers best guess. As a result image quality has been reduced.

The problem continues after the photographer has up sampled the image to 100 MB. The customer buys the image and determines that it is too big for their needs so they down sample the image losing data and quality in the process. Now the buyer has lost the original high quality when all they needed was a small file for a brochure.

Bigger is not always better.

Now that being said the photographer should always provide the largest original possible for optimal image quality.

Interpolation should only be used as a last result.
Here is a sample of what interpolation can do.

Look at the feathers around the birds eye, they are softened more than the original as well as other details due to interpolation. For more information on interpolation check out DPreview.com

Technorati Tags : image | interpolation |

Posted by Thibaud on 05:28, March 1 2005

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