scanners mary van court
DESCRIPTION
Mary Van Court's presentation on optimal scanner settings for the RML Rendezvous, March 10, 2010.TRANSCRIPT
Not Through a Glass, Darkly
Tips and Tricks forOptimal Scanner Settings
Mary 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 filesMost 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
dpi = dots per inch
Select the resolutionFor web display100 dpi
For standard printing240 – 300 dpi
For glossy printing or postersScanner maximum
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
Does the scan get lighter or darker when you increase the brightness?
Settings are not consistent from scanner
to scanner
Optical Character Recognition (OCR)
ALots of programs to convert paper image to text
Need to scan at 300 – 400 dpi
97-99% accurate
Can create searchable image
Post scanning editingVariety 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.