QUESTION: What is PDF?
ANSWER: PDF stands for Portable
Document Format. It is a file format that describes
the text and graphics in documents. It was
invented by Adobe Systems Incorporated.
Because it describes the text and graphics in
documents, PDF is considered to be a
page-description language.
Note, however, that PDF is quite different from
other page-description
languages (such as PostScript
and PCL) because — unlike
other page-description languages — PDF can do much
more than simply describe the appearance of a document.
See What is Adobe Acrobat?
for more information about this.
Software that supports
PDF viewing (such as the Adobe
Acrobat software) understands the PDF format.
Here is an example of a PDF file:
%PDF-1.0
1 0 obj
<<
/Type /Catalog
/Pages 3 0 R
/Outlines 2 0 R
>>
endobj
2 0 obj
<<
/Type /Outlines
/Count 0
>>
endobj
3 0 obj
<<
/Type /Pages
/Count 1
/Kids [4 0 R]
>>
endobj
4 0 obj
<<
/Type /Page
/Parent 3 0 R
/Resources << /Font << /F1 7 0 R >>/ProcSet 6 0 R
>>
/MediaBox [0 0 612 792]
/Contents 5 0 R
>>
endobj
5 0 obj
<< /Length 129 >>
stream
BT
/F1 12 Tf
72 648 Td (Here is a line of text.) Tj
ET
endstream
endobj
6 0 obj
[/PDF /Text]
endobj
7 0 obj
<<
/Type /Font
/Subtype /Type1
/Name /F1
/BaseFont /Helvetica
/Encoding /MacRomanEncoding
>>
endobj
xref
0 8
0000000000 65535 f
0000000009 00000 n
0000000074 00000 n
0000000120 00000 n
0000000179 00000 n
0000000322 00000 n
0000000415 00000 n
0000000445 00000 n
trailer
<<
/Size 8
/Root 1 0 R
>>
startxref
553
%%EOF
The PDF file depicted above describes a one-page document with one line of text
that is positioned one inch from the left
edge of the page and nine inches from the
bottom of the page.
The PDF file format is somewhat complex. If
you'd like to understand it, you can
read Adobe System's
Incorporated's "PDF Reference."
The current version of it is located
here.
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