HP 1100A - Manual (Page 178)

178 Appendix G Scanner resolution and gray scale EN
Resolution
Generally, the ideal scanning resolution is 150 dots per inch (dpi).
Changing the size of the image after it has been scanned affects the
resolution. Therefore, before setting the scanner resolution, it is
helpful to determine what the final image size will be. For example,
you might want to scan an original that is 76 x 127 mm (3 x 5 in.), but
there is only room for a 38 x 63.5 mm (1.5 x 2.5 in.) picture in your
document.
Resolution
Size of original Size after scanned and
altered Recommended scanner
resolution
76 x 127 mm
(3 x 5 in.)
152 x 254 mm
(6 x 10 in.)
38 x 63.5 mm
(1.5 x 2.5 in.)
150 dpi
300 dpi
150 dpi
76 x 127 mm
(3 x 5 in.)