Definition of a Legal Blackline Document

By Elissa Englund

Updated September 28, 2017

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Legal blacklining, also called redlining and document comparison, is a way to compare two documents in a word processing program and display only what changed between them.

Uses for Blackline Documents

In the legal field, the blackline option allows lawyers to compare versions of documents or contracts to see what has been revised. In publishing, blacklines show an author the revisions that were made during the editorial process and track the progress of a manuscript. In finance and banking, blacklines easily show adjustments in data without having to review an entire spreadsheet or document to see the changes.

Software for Legal Blacklines

Many word processing programs have an option to create a legal blackline document. This function compares two files by creating a new third file that shows only the changes that exist between the two documents. It does not revise the native files at all. In addition, many software programs provide high-level legal blackline services, in which users can collaborate on the versions after they have been compared.

How to Blackline in Microsoft Word

Microsoft Word is a common program that provides a legal blackline option. To perform a blackline in Word 2003, open one of the two documents you want to compare. Click on the "Tools" menu and select "Compare and Merge Documents." Check the box that reads "Legal blackline" and choose the second document you want to compare. Click "Compare." This will create a new file that you can save and revise without changing the original documents.