Use of a Hewlett-Packard ScanJet image digitizer as an X-ray powder photograph densitometer

Abstract

A densitometer trace of an X-ray powder photograph is easily obtained by making a contact print and scanning this with a Hewlett-Packard ScanJet using the programs SCANGAL, IMAGE EDITOR and SCANNER on SCANNING GALLERY in the WINDOWS environment. The light in the ScanJet from a halogen lamp (50 V, 42.5 W) is reflected by the print and detected by a charge-coupled device. The instrument measures reflected light intensity. The flatbed ScanJet has an optical resolution of 2550 dots yielding 300 dots per inch (d.p.i.) over the A4 page. Output resolution is selectable and runs from 38 to 600 d.p.i. The density and mode (binary, dithered, greyscale and scaling) may be adjusted. However, when scanned, the regular negative Guinier photograph does not give clear images because the rough developed-emulsion surface scatters light indiscriminately, producing dark images and lacking in resolution.