Fujitsu ScanSnap N1800 Operator's Manual page 316

To automatically set a keyword for a PDF file, change the settings as shown below.
ATTENTION
Conversion to searchable PDF may take extra time.
The scanner may fail to correctly recognize the following kinds of documents (characters) as
text. However, by changing the color mode and/or improving the image quality for scanning,
such documents may be successfully recognized.
Handwritten documents
Documents including smaller characters and scanned in low quality
Skewed documents
Documents including texts written in italic characters
Superscript/subscript letters and complex mathematical formulas
Characters are written against an unevenly-colored or patterned background
Example: Shaded characters
Documents containing a lot of characters to which effects are applied
Example: Characters to which effects such as Shadow and Outline are applied
Documents with a complex layout and documents with image noise (uneven color, paper
overlap, smudges) may take longer for text recognition to process.
If the same character string is marked at multiple locations of a document, the same keyword
is added to the PDF file multiple times.
The total number of characters for keywords is limited up to 255 characters, including
delimiters between keywords.
When keywords are viewed in Adobe Acrobat and Adobe Reader, the appended quotation
marks (") may be found at the beginning and end of keywords.
1. On the [Scan Settings] window, select the [Save] tab.
2. Press the [Text Recognition] button.
The [Text Recognition] window appears.
6.9 Setting the Scan Options
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