Samuel J. May Anti-Slavery Collection
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illustrationConversion to Digital Format
The approaches to conversion used in this project built on the seminal methods developed in the Cornell University Library and articulated by Kenney and Chapman (1996), and rearticulated by Kenney and Rieger (2000).[1]  For each type of material to be scanned, we determined the appropriate digitization benchmarks, then selected appropriate digitization methods. 

Review of the collections resulted in the identification of three basic types of material appropriate for digitization: standard-sized printed material, oversized printed material, and three-dimensional items. Some printed material such as pamphlets and songbooks, with no color but a wide tonal range, could be captured effectively as 300 dpi 8-bit grayscale TIFF images on a Xerox Docuimage 620s flatbed scanner. Much of the flat material (such as ribbons, some sheet music, and some broadsides) contains color information that had to be retained, so HP, Microtek, and Agfa color scanners were used. We scanned them as 24-bit color TIFF images, with an appropriate grayscale/color bar scanned with each document to ensure color matching, at 400 dpi (although the final size depended on the significant features of  each document).  Because all of these items have intrinsic value as physical objects, non-damaging techniques were used to prepare them for scanning. Most were in good physical condition, but some are low contrast documents (the tonal difference between the medium and support is low). Great care was taken in handling these items and in adjusting capture settings (brightness, contrast, tonal reproduction curves) to produce digital files of high quality, fidelity, and readability. 

The largest percentage of the collection is composed of three-dimensional or oversized materials. We took two approaches to digitizing this material. Most of the items were shot using a PhaseOne PowerPhase digital camera mounted on a ZBE Satellite copy stand in our digital photo studio and an Epson 1640XL Graphics scanner. The PhaseOne camera allows digital images of up to 140MB in size, although our default was to shoot at 600 dpi. Our experience in capturing items for the H. F. Johnson Museum at Cornell demonstrated that quality digital imaging with a digital camera is a slow process; for most artifacts, we averaged only 20-30 scans a day. 

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Division of Rare and Manuscript Collections Cornell University Library

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