Scanners Mary Van Court

Not Through a Glass, Darkly
Tips and Tricks forOptimal Scanner SettingsMary Van Court
University of WashingtonHealth Sciences Library

Before you start…
What do you want to scan?
What kind of digital file do you want?
Do you have the right software?

Do you want to scan a photo or a multipage document?

Photos are usually scanned asJPEG or GIF files
Use JPEG for complex images
> 16 million colors
Not as sharp as GIF
Use GIF for line art or logos
Sharper than JPEG
256 colors

Multipage documents are usually scanned as PDF or TIFF files
Most people are more comfortable with PDF
Some applications require TIFF (such as Ariel for Interlibrary Loan)
Lots of programs to convert between theme.g. DocMorph from the National Library of Medicine (http://docmorph.nlm.nih.gov/docmorph/).

Look at the software
The software that came with your scanner will usually do a good job of scanning photos, but will it do what you want?

Every scanner/software combination is different

Some walk you through the process step by step

Some show all your scanningoptions on one screen

Some give you a few optionsand make you look for the rest

Sometimes there are multiple places to look

Select the file format

Select the resolution
For web display
100 dpi
For standard printing
240 – 300 dpi
For glossy printing or posters
Scanner maximum
dpi = dots per inch

Sometimes the resolution setting is explicit

Sometimes there are sliders
This one shows the relationship between resolution and file size.

Select the image type/mode

Sometimes it’s more cryptic
24-bit color
256 colors
8 colors
RGB colors
Line drawing
Half tone
Text + photo
Generation

Set the physical parameters
It’s often automatic, but sometimes you have to set:
Paper size
Flatbed scanner vs. document feeder
One or two-sided original
Scanner accessories

Adjust the image parameters
Brightness
Threshold
Contrast
Dithering
Despeckle

Sometimes settings are pictures – not words

Settings are not consistent from scanner to scanner
Does the scan get lighter or darker when you increase the brightness?

Optical Character Recognition (OCR)
A
Lots of programs to convert paper image to text
Need to scan at 300 – 400 dpi
97-99% accurate
Can create searchable image

Post scanning editing
Variety of software
Lots of different features
Shop around for what you want

The bottom line is …
There are a lot of choices. Keep looking until you find one that works for you.

Scanners Mary Van Court

by Patricia Devine

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