Input Devices, ContinuedScannersGrey scalescannersColor scannersScanner typesA scanner allows you to copy a photograph, a drawing, or a text page intothe memory of the computer. It does this by measuring tonal or color valuesand converting them into a binary code that the computer can digest. Youmay then “clean-up” the image using the appropriate software programbefore printing a final copy for reproduction. Software for the scanner is asimportant as the scanner. The software provides for image manipulation andexport format compatibility. A scanner is particularly useful for copyinglarge amounts of text or images not previously saved on disk that nowrequire revision. When using a scanner, be careful not to violate an existingcopyright.Grey scale scanners read tonal values and assign density code numbers. Thedensity code is available from 16 to 256 levels of grey. For general-purposework, select a software program that offers a minimum of 64 levels of grey.A color scanner reads color value and assigns it a binary code for export.This scanner will range from 70 to 600 dots per inch (DPI) with 24 binarydigits (bits) of color. For general-purpose work, select a software programthat offers a range between 300 and 600 dpi.The four types of scanners are the hand scanner, the flatbed scanner, thecopystand scanner, and the slide scanner.HAND SCANNERS: Hand scanners are useful for small quantity scanning.They read portions or excerpts from a document page into the memory of thecomputer.FLATBED SCANNERS: Flatbed scanners scan pages out of a book. Theyscan an entire one- or two-page spread in one view.COPYSTAND SCANNERS: Copystand scanners are capable of scanningthree-dimensional objects.SLIDE SCANNERS: Slide scanners scan slides and transparencies intomemory. Scanners used to scan slides and transparencies require a mirroredor reflective attachment.Continued on next page3-9
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
