I.R.I.S. Readiris 14 for Windows User Guide - Manual (Page 139)

How to
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H
OW TO IMPROVE THE RECOGNITION RESULTS
The quality of the recognition results depends on a number of
factors:

the document language
Make sure you select the right language in the Language list. See
the section Document Recognition Options for more
information.

the quality of the scanned documents
If the scanned documents are too bright, or too dark, Readiris
will have trouble recognizing them. Luckily there is a feature
that allows you to adjust the quality of scanned documents. See
the section Adjusting the Image Quality to learn how to do so.

the scanner settings
If you are using a scanner to scan documents, the image quality
is also linked to the scanner settings. See the section Selecting
the Scanner Settings to make sure the right settings have been
selected for your scanner.
Make the scan resolution is set to 300 dpi for regular documents
and to 400 dpi for small print and Asian languages.
H
OW TO SCAN MULTIPLE DOCUMENTS
In Readiris there are a number of features that allow you to scan and
process multiple documents easily in Readiris.