Scanners “The Computer as an Educational Tool: Productivity and Problem Solving” ©Richard C. Forcier and Don E. Descy

Scanner Functions Graphics and photos Graphics and photos Digital files Digital files Data entry Data entry

Scanner Types Flatbeds Flatbeds Sheet-fed Sheet-fed Film/Slide Film/Slide Handheld Handheld Portable Portable

Flatbed Scanners General purpose General purpose Multifunction Multifunction Most common Most common Affordable Affordable

Sheet-fed Document-management tasks Document-management tasks Office scanners Office scanners Compact Compact

Film/Slide High resolution High resolution Scans slides, films, negatives, and transparencies Scans slides, films, negatives, and transparencies Light is projected through the original to the other side. Light is projected through the original to the other side.

Handheld Works well for awkward sizes Works well for awkward sizes Several passes over a regular- sized document Several passes over a regular- sized document Scans can turn out uneven. Scans can turn out uneven.

Portable Lightweight and compact Lightweight and compact About the size of a bestseller book About the size of a bestseller book Image quality isn’t as good. Image quality isn’t as good.

Scanner Features Resolution Resolution Bit depth Bit depth Dynamic range Dynamic range Software Software

Resolution How many dots per inch (dpi) a scanner can record How many dots per inch (dpi) a scanner can record Optical vs. interpolated resolution Optical vs. interpolated resolution 300 dpi is sufficient for most uses. 300 dpi is sufficient for most uses.

Bit Depth Amount of information that the scanner can remember about each pixel Amount of information that the scanner can remember about each pixel The higher the bits, the more details a scanner can record about an image’s color or gray scale. The higher the bits, the more details a scanner can record about an image’s color or gray scale. For most home uses, a 12-bit scanner is adequate. For most home uses, a 12-bit scanner is adequate.

Dynamic Range Similar to bit depth Similar to bit depth Measures the ability of scanners to reproduce tones Measures the ability of scanners to reproduce tones Standard flatbeds typically have a range of 2–2.5. Standard flatbeds typically have a range of 2–2.5.

Software TWAIN drivers allow a piece of hardware to work with a computer system. TWAIN drivers allow a piece of hardware to work with a computer system. Different software caters to different audiences. Different software caters to different audiences. Research software according to needs Research software according to needs