laboratory notes
Scanners are widely used for easy and fast image acquisition. Spatial resolution ranges from 300 up to 1200 dots per inch (d.p.i.) and, for black-and-white acquisition, 256 grey levels (1 byte) are associated with each pixel. These features are potentially adequate for a quantitative acquisition of the two-dimensional X-ray diffraction pattern from a fibre sample of polymer recorded by photographic film. An indirect approach was reported by Calos & Kennard [J. Appl. Cryst. (1991). 24, 73], who described a system for reading X-ray powder film. To avoid the problem of the scattering of the film surface in the reflective acquisition mode, they printed the film on photographic paper; thus, the diffuse light scattering was eliminated. In the present note, the use of a scanner system for a quantitative acquisition of films in a direct way is reported.