Cleaning Slide Scans

Whenever you start doing high-resolution scanning of slides or film, you will immediately notice how much dirt and dust in in the surface! Freshly processed material can have this problem, but it gets really bad with older film. A lot of this material is not even visible with standard slide viewers, but is very obvious with high-resolution digital scans.

This image represents a small section of a realist-format picture that had been converted to grayscale and enhanced do to extreme fading of the image on the Ektachrome original. These slides were about 45-years old and the material visible here represents dust, fibers, and fungal contamination of the emulsion. The classic camel's hair brush or compressed air can can do a pretty good job on fresh accumulations of grime, but much of this material had settled into the emulsion.

The solution to this problem was digital editing. My favorite software for preparing Holmes stereoviews is Adobe Photoshop Elements   . The software runs about $90 new and is bundled with many Canon hardware products such as cameras and scanners. Versions 4.0 and up have a really neat editing tool - it looks like a little Band-Aid and is called the Spot Healing Brush Tool. It does a fantastic job of blending such imperfections into the background and is infinitely quicker than other approaches to editing:

As you can see here, just a few minutes were required to eliminate the worst of the grime. Lots of very small stuff remains, but particles of this size range will be impossible to see/resolve in the finals views. All in all, a neat solution to an annoying problem!

Ralph E. Taggart (taggart@msu.edu)