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 PDF
File Types
Here's a crash course on the different types of Adobe pdf
files and reasons for selecting each.
The choice of file type is sometimes determined by the source hard copy
material or budget, but other times can be selected based on the goals of your particular project.
To select a file type, ask yourself:
"How will the digital documents be used?"
"Does the text of the document need to be searchable?"
"Is file size important?"
"Does the PDF need to look EXACTLY like the original hard copy?"
Here are your three options:
PDF IMAGE ONLY -
These documents contain only a bitmap picture of the original document. They do not contain searchable text.
- Advantage - Provides exact copies of originals and is the lowest cost
pdf option
- Disadvantage - Search and retrieval is limited and the file sizes can
be larger than .pdf normal
- Popular uses - Applications where the primary concerns are; the graphical
integrity, cross platform compatibility and or image portability. Documents containing mostly or all hand writing.
i.e. scientific notebooks, engineering or architectural drawings that have very little searchable text and documents
containing mostly photographic images are perfect for pdf image only.
- Go to Sample Files
PDF NORMAL
- These documents contain electronic text that is scalable and can be indexed, searched and copied. Page formatting
and graphical images are preserved as best they can.
- Advantage - Smallest files sizes. Significantly smaller than pdf image
only, Best on screen display clarity that is perfect for online distribution.
- Disadvantage - Originals are converted to formatted electronic text.
They don't look exactly like the originals. All graphics and formatting are preserved, but substitute fonts are
sometimes used where exact matches are not possible.
- Popular uses - Applications when the content of your documents needs
to be searchable and when file size is critical or to give documents the best possible on-screen or printed appearance.
Any application where the graphical integrity of the text is secondary and
the primary function is to locate searched text for reference. Documents to be placed on the internet where smaller
document sizes are very important. i.e. Human resources files are perfect for pdf normal.
- More about - If, during the Capture OCR process, a word cannot be recognized
to the specified confidence level, Capture (by default) substitutes a small portion of the original bitmap image.
Capture's "best guess" of the suspect word lies behind the bitmap so that searching and indexing are
still possible. However, one cannot count on 100% search accuracy of these bitmaped words. The document still appears
"visually accurate" since the bit mapped version of the word is displayed. (Many traditional OCR type
applications replace unrecognized words with random characters, such as tildas or asterisks.) Unfortunately, the
words that are left as bitmaps give the document a less than polished look because fully scalable and bit mapped
text can appear together within the same line.
- Go to Sample Files
PDF IMAGE + TEXT -
These documents combine features of .pdf image only and .pdf normal documents. Like PDF-Image Only, the complete
original bitmap is used to display and/or print the entire page, so the result is an exact representation of the
scanned page. And like PDF Normal, OCR is done during the Capture process so that the document is searchable. However,
the recognized (OCR) text is hidden behind the bitmap as an invisible second layer. This assures the document is
identical in appearance to the original yet provides all the advantages of searchable text.
- Advantage - Searchable text that ensures the document is identical in
appearance to the original. The bitmap picture ensure ZERO possible errors on the page.
- Disadvantage - Results in the largest file sizes and the pages will
not display as quickly or cleanly on screen since the entire page is a bitmap and neither fonts nor line drawings
are vectorized.
- Popular uses - Applications where the original graphical integrity is
primary and file sizes are not important. CD-Rom or company intranets. i.e. Court or legal and public access documents,
parts manuals of all kinds, books, magazines & catalogs, are all perfect for archiving with pdf image + text.
- Go to Sample Files
PDF conversion can be performed from three original image
sources:
- From a document
scanning project.
- From a microfilm
scanning project.
- or if you already have electronic images as an independent
step to your existing images.
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