Selecting Microfilm for Newspaper Digitization

The quality of the microfilm from which one scans can make a big difference in the ability of your readers to search the final digital product. Many things influence the quality of the digitized copy and, particularly, the ability of an optical character recognition (OCR) program to make keyword searching effective.

Some standard references regarding microfilm quality and selection for digitization include:

Summary of Microfilm Readings that Meet National Standards for Digitization

  • Visual inspection with a 10x scale lupe shows crisp text
  • Reduction ratio less than 20x
  • Resolution of 5.0 or higher
  • Density on a reel of film runs between 0.90 and 1.20
  • Difference in density readings between exposures and within an image is no higher than 0.20.

Microfilm Standards and Quality Preliminaries

  • Use the second generation of the microfilm, if possible. The first generation master is the film that comes right out of the camera and may be irreplaceable. The second generation, often called the print negative, is the one ideally used to make duplicate film or from which to scan. The third generation, named the service copy, is a positive and is the copy that readers used in your reading room. It is not, generally speaking, suitable for scanning as positive film has more “noise” than negative film and this “noise” will weaken the OCR process outcome. In addition, service copies are usually scratched by use in a microfilm reader and those scratches will also impact the quality of a scan.
  • Look at the service copy to see if you can expect the negative to be marred by any of the following problems.

Out of focus.

Example of out of focus film from a newspaper page sample

Lights out of place when filming, leading to glare obscuring text.

Example of glare obscuring the text of a digitized newspaper.

Camera not perfectly parallel to the page can lead to a trapezoidal shape and skew, affecting OCR quality and the reliability of keyword searching.

Example of film with trapezoidal shape from a newspaper page

  • Use the visual inspection of your service copies, keeping in mind all of the above, and make a judgment about how many pages out of the whole reel are legible.

To do a more sophisticated analysis of your film suitability, use the reference books on microfilm standards listed above to measure:

  • Resolution
  • Reduction Ratio
  • Density

Remember! Scanning vendors can make good digital images out of less than perfect film but start with the best film you can locate!