Myths About Slide Scanning and Negative Scanning: Higher Resolution is Better

Myth: You should always scan at the highest available resolution. Higher resolution is always better.

What resolution should I use to scan my slides and negatives? We get this question all the time. We have become acustomed to believing that more is always better. Sometimes this isn't the case.

The short answer to this question for most of our customers is 2000 PPI - the lowest resolution at which we offer our scanning services. Why?

Only a small percentage of the films that we see benefit from scanning at higher resolutions. Generally speaking, only film that is shot on very good equipment (i.e., probably not a point and shoot 35mm camera) using fine grained film (i.e., not 400 speed) with good technique (i.e., well exposed, camera on a tripod) might regularly contain detail beyond that captured by scanning at 2000 PPI.

Let's look at a specific example:

Image scanned at 2000 PPI 200% crop of an area (click for the full-sized, uncropped JPEG image 4.2MB)	Same image, scanned at 4000PPI 100%crop (click for the full-sized, uncropped JPEG image 11.6MB)

This image was shot on Kodachrome film during the 1980's. It has been scanned on the Nikon 5000 ED scanner with ICE enabled but no grain reduction, sharpening or any other corrections applied.

As you can see from the sections of the scans shown above, The 2000 PPI and 4000 PPI scans are basically identical with respect to the detail extracted from the film.

Time and again, we see this with a variety of films from different manufacturers and time periods. Simply put, most cameras (and most photographers) don't capture more detail than is extracted by a 2000 PPI scan. There are, of course, exceptions to this. The only way to know for sure is to scan your own film at both resolutions and compare the results.

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