Microsoft has used the docx file format for Word documents since the release of Word 2007. It is an open standard defined by ISO/IEC 29500-1:2016. Docx is the most common format for rich-text documents. It is used for everything from business correspondence, newsletters and flyers to complete books. Rich documents can be produced by embedding objects such as picture art, drawn-shapes and tables.
Under the covers a docx file is actually a zip file that wraps several files containing the text and objects of the document. You can be explore the internals of a docx file by renaming the file extension from .docx to .zip and unzipping the file. This will expand to a directory containing the content that makes up the document.
Docx files are easily editible using Microsoft Word or alternatives such as LibreOffice or OpenOffice. This makes it ideal for creating and updating content but it also can be a disadvantage as it does not prevent changes when the document is shared with others.
The PDF file format was developed by Adobe Inc. to allow electronic publishing of rich documents containing text and images. It is an open standard defined by ISO 32000-2:2020. The PDF format is designed to display pages visually true to the original document when on different systems.
The format is convenient for sharing documents that should not be changed. PDF documents are not easy to edit directly. It usually easier to edit the document it its original format and re-create the entire PDF. The PDF format supports encryption of sensitive documents and digital signing to prevent changes being made after publishing. These are valuable features for commercial and legal documents.
Since many PDF documents were obviously originally created in Word and they contain all of the text and Images of the original, then why can it be so difficult to just convert it back?
The main reason for this is to do the design of the two formats:
Word Docx is a word-processing format. It knows about the document structure. It knows where paragraphs
start and end and about text-columns. It knows that a picture is positioned relative to a particular paragraph
and that it should move with that paragraph. It knows what a table is and that it has cells containing text or objects.
On the other hand PDF is a page-display format. It only knows about text characters and images or drawings and where they are positioned on a page.
It does not know which text forms a paragraph or how the page is divided up into text-columns. It may not even have
space characters between words, instead just relying on the positioning of the characters to separate the words visually on the page.
Objects such as tables in MS Word have no meaning in PDF. A table has to be detected by looking at character positions and line drawing operations.
PDF is related to the Postscript printer control language and content in a PDF file is defined by display operations rather than structure.
Text and drawing operations can jump around the page in ways that may be efficient for display or for printing but the relationship between page content is lost.
A lot of document structure information is lost when the document is output to PDF. The PDF to Word converter has to try re-create this structure by examining the document layout and guessing what it "looks" like.
BusyPDF converts your pdf documents to the latest MS Word docx file specification. Unlike documents created on other sites you will not see a "Compatibility Mode" warning when you open your converted document in MS Word.
MS Word displays the Compatibility Mode warning when the document was created using an older version of the MS Word specification. This warning also lets you know that MS Word will not allow you to use newer features when you need to edit the document.
Many PDF documents contain Scalable Vector Graphics. These are images that can be scaled larger or smaller without losing their crisp definition.
They are used in cases where high quality is important such as for company logos in document headers or for
detailed line-art in marketing or technical documents.
Scalable Vector Graphic files have a .svg extension.
Common bitmap picture formats such as jpg or png will become blurry or pixelated when scaled.
BusyPDF converts scalable vector graphics to MS Word Shapes and retains the sharpness and scalability of the original images. If document quality is important to you then you will want your pdf to be converted to MS Word in scalable vector format
Other document conversion sites downgrade a scalable vector graphic to a bitmap and then insert it as a picture in the MS Word docx file. The picture will be noticeably fuzzy at the edges even at a scale of 1:1. The converted MS Word document will not look as sharp or professional as the original PDF. Another disadvantage is that text within the graphic will no longer be editable or searchable.