PDF Proofreading Markup

/ May 10, 2022

Updated May 12, 2026

Extreme close-up of a typewriter with a red-and-black ribbon. The word "Proofreading" is centered above the type guide on an otherwise blank page.

CMOS 2.138 in the Spotlight

Copyeditors typically work in Microsoft Word or Google Docs or the like, making and suggesting changes directly in the document, which at that stage is still referred to as a manuscript. Proofreaders come in at a later stage, after the manuscript has been converted and formatted for publication in a program like Adobe InDesign.

Proofreading can still be done with pencil and paper (as on a printout), but it’s more common these days to mark corrections on the screen, in a PDF file that shows how the publication would look in print. Either way, most proofreaders are annotating a copy for the typesetter rather than making actual changes to the file.

A convenient way to mark PDFs is by using the commenting tools in Adobe Acrobat. These tools are available in both the free and paid versions of the program, making it easy to try them out.

Before we check out how this works, let’s review the traditional marks.

Traditional Proofreaders’ Marks

Figure 2.6 in CMOS lists the traditional proofreaders’ marks and what they mean:

A list of proofreaders’ marks organized by category: operational marks (for deleting and adjusting text), typographical signs (for changing font and capitalization), and punctuation marks (for inserting commas and the like).

The marks in figure 2.6 are intended to be written in the margins. In the text itself—where space for writing is limited—most of the work is done with carets and lines. For example, a slash through a capital letter would mean to lowercase that letter, a single underline would mean italics, double and triple underlines would mean small caps and all caps (respectively), a caret would mark an insertion, and so on. (All this is covered in CMOS 2.124–38.)

Figure 2.7 shows how the marks in figure 2.6 would be applied. Here are the first several lines of that figure:

The heading and first ten lines of text of a page annotated by hand with proofreading marks.

What would this pencil-marked page look like as a marked-up PDF file?

Proofreading in Acrobat

CMOS 2.138, on proofreading tools for PDF, outlines some of the basic principles, especially as they would apply to using the commenting and markup tools in Adobe Acrobat.

However, there is no single “correct” way of using the tools in Acrobat to annotate a document. For example, you could simply use the drawing tool as if you’re working on paper and add a virtual pop-up note in the margin wherever an explanation is needed. But there are usually some better options available.

To demonstrate a few of these for this post, we typed the text of figure 2.7 into a page-layout program, saved the document as a PDF file, and then used Acrobat Reader (the free version of Acrobat) to add the markup (except for the line and dots that mark up the phrase “and a craft” and correspond to a marginal “stet” in the seventh line of the main text in the original figure; markup added in Acrobat can simply be deleted or revised rather than stetted).

The markup in the following figure isn’t meant to be definitive—again, Acrobat’s tools allow for a variety of approaches—but we hope it will serve as an introduction to the process:

A page annotated with proofreading marks in Adobe Acrobat Reader. The first 7 of 49 comments are listed in a pane to the right of the document.

Note that the markup appears in two places: on the page itself and in a corresponding comments list on the right-hand side of the page. (To display the comments list in Acrobat, click the comments icon in the right-hand pane.)

Entries in the comments list are added automatically for each new mark (markup tools are available from the floating comments toolbar to the left of the document). Our document ended up including forty-nine items. Here’s a brief rundown of the first several:

  1. To tell the typesetter to center the heading, we used the freehand Draw tool to add the traditional marks for centering. Then we typed an instruction—“center heading”—and posted it to the list. The two marks—⊐ and ⊏—are treated as one in the comments list. Each stroke in a freehand drawing will remain grouped in this way until you click the toolbar again. You can then add a comment by double-clicking the grouped marks with the Select tool (the arrow).
  2. To mark the word “As” in the heading (the A should be lowercase), we used the Replace selected text tool and then typed “as” in the corresponding comment. (Acrobat spell-checks your comments for you as you type them, but you should still be careful when entering corrections.)
  3. To mark the erroneous indents in the first two lines of text, we once again used the Draw tool. But this time we drew ⊏ and ⊐ separately and added a comment to each.
  4. To mark a change from “used” to “use” in the first line of text, we again used the Replace selected text tool and typed “use” as the new text. (We sorted our comments by their position on the page, so this change is listed between the changes to the indents.)
  5. To ask for quotation marks before and after “but please print the proofs in a larger type” (including the final period), we drew an inverted caret in each spot—⋁ and ⋁—and typed two separate comments: “add opening double quotation mark” and “add closing double quotation mark.” Alternatively, we could have used regular carets as in the hand-marked version of figure 2.7. And we could have grouped the marks and commented only once.
  6. To mark the bad break in the fourth line of text, we used the Highlight tool and added a comment to that (not shown here): “bad break: ridicu- / lous.”
  7. To mark the typo in the fifth line of text (“familar”), we used the Insert text tool and typed a lowercase “i” in the comment (not shown).
  8. Then we marked the typo in “except” using the same tool as in steps 2 and 4.
  9. And so on.

Figure 2.7 is full of errors that were added to the document for demonstration purposes only. In real life, the process will almost always be neater. But even a messy-looking document can be easy enough to manage—thanks to the list.

Keeping Track

Some of us worry about the typesetter missing a change if it’s not sufficiently visible on the screen. We’re used to working on paper, where everything depends on the typesetter seeing our marks.

But that’s what the right-hand pane is for. Whenever you insert a mark or comment of any kind, it gets added to the list automatically. The typesetter can then click through the list, comment by comment, and make each change as it comes up. Plus, as each item in the list is selected, Acrobat outlines the visible annotation in the document to make it stand out on the page.

To help keep track of where they’ve been, typesetters and others can set the status for each comment as they work through the list (by right-clicking a comment or by using the three-dot menu). For example, the following item in the comments list has been marked as completed (note the green checkmark):

A comment in Adobe Acrobat Reader marked as completed (with a white check mark in a green box). The comment, “center heading,” is labeled “proofreader” and dated May 6.

So even a change like the one that adds the missing i in “familar”—which appears on the page as a tiny caret next to a miniature comment icon—shouldn’t be missed. For good measure, you can click through the comments on the original marked-up PDF and double-check those against the corrected pages to look for any omissions.

Still, it’s tempting to add a simple comment (using the Add a comment tool) to draw the typesetter’s attention to a less-than-obvious change. The occasional comment of this type is fine. We added one next to the correction calling for “A.D.” before “1165–70” (the text of the note, not shown in our figure, says to put the letters in small caps).

But resist adding too many stand-alone comments. The markup tools described above allow for their own comments (whether as instructions or corrections—or both),* and these stay with the mark, so you shouldn’t need separate comments in addition to those except for general instructions and the occasional clarification.

If you want to create a more visual presentation, there are some other options. For example, Acrobat includes a stamp tool (under All tools > View more > Add a stamp). You can use the stamp tool to add or import your own set of proofreading marks to use and reuse.

There are also tools for typing visible instructions right on the page (including as a boxed Text callout with an adjustable arrow). To find out more about these and the rest of Acrobat’s commenting tools, consult Adobe’s Help pages. Start with the page that covers how to insert text and go from there.

✏️ ✏️ ✏️

Acrobat’s tools have improved over the years, but they can still be cumbersome to use. If you’re having trouble with them, and you have the option of working on paper, you could make a printout of the file, mark it up by hand, and scan the results, saving the scan as a new PDF file. But you’ll lose the benefit of the original PDF’s searchable text—and the comments list.†

* To differentiate between a correction and an instruction within a single comment, the instruction can be set in square brackets, on a separate line.

† Not to mention Undo (Ctrl-Z in Windows or Cmd-Z on a Mac) and Redo (Ctrl-Shift-Z [or Ctrl-Y] or Cmd-Shift-Z), which can be especially helpful with the drawing tools.

Typewriter photo by Michail Petrov / Adobe Stock.

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