Review of CommonLook PDF



The following is an evaluation of CommonLook PDF 4.2.4. Please refer to the CommonLook website for current information.

CommonLook PDF logoPDF files have long presented a challenge in accessibility terms. Unlike HTML, a PDF document’s text and graphics must be “tagged” for reliable use with assistive technology. Ensuring PDF files are properly tagged can be complicated and time-consuming. To-date, most tagged PDF is automatically generated without meaningful quality control of the tags. For AT users, the results range from slightly to extremely frustrating.

Software to produce tagged PDF has improved in recent years. Adobe’s Acrobat and InDesign, Microsoft’s Office products, and the free Open Office alternative to Microsoft Office are all capable of generating high quality tagged PDF.

That said, most document authors don’t do a great job of setting up the source file; doing what’s necessary to make the document accessible at the outset prior to PDF creation. Even if that’s done right, so far most PDF creation software doesn’t do a perfect job of creating tagged PDF. Some touchup is usually required on the output PDF file; that’s where CommonLook PDF comes in.

The Basic Options

It’s almost always best to ensure your PDF file is tagged when it’s first created; these are usually the highest-quality tags that can be automatically produced. The likelihood of human and software errors, however, compel verification of PDF files as properly tagged and accessible, and the correction of any errors found, before distribution.

As of January, 2013, two tools are available that provide the ability to both check and correct PDF tags; Adobe Systems’ Acrobat Professional and CommonLook PDF, a plug-in to Acrobat Professional produced by NetCentric Technologies.

You can certainly use Adobe Acrobat alone to do the job, but you’ll have to figure it all out yourself. CommonLook PDF provides many additional features to standardized and speed verification and improve quality: a methodical workflow, advanced table structure editor, various efficiency tools, comprehensive reporting, integration with website auditing software, and more.

Whether these features justify the substantial price of CommonLook PDF (a single-user license is $1,299) is first and foremost a function of volume. If you’ll be checking and correcting lots of PDF files – and especially if those files include lots of complex tables – then CommonLook PDF’s ROI could be substantial. If your need is only occasional, you’re less likely to go through the software’s learning curve and discover it’s full potential as a productivity enhancement. On the other hand, if you’re only an occasional user then from a quality point of view, you need a systematic process such as the one CommonLook PDF offers.

As always, you need to think it through based on your particular circumstances.

A word about accessibility: While the product includes many keyboard shortcuts, CommonLook PDF demands heavy usage of a mouse. Verification work by its nature requires the ability to assess color, alternate text and other properties of documents that need visual review to determine whether and how the content is accessible. For this reason, CommonLook PDF isn’t itself especially accessible, but nor would we expect it to be for the functions it performs.

Standards Used

At the time of review, CommonLook PDF’s checkpoints are based on the current US Federal §1194.22 regulations (e.g., Section 508). CommonLook PDF Oklahoma Edition uses that state’s rules). The company has announced their intention in the near future to support PDF/UA, the new ISO standard for accessible PDF technology, and through that, to support WCAG 2.0. For now, it’s possible to use CommonLook PDF as part of a WCAG 2.0 conformance process, but the software does not currently provide checkpoints to meet that standard.

The Process

You’ll need at least a basic knowledge of accessibility before CommonLook PDF will mean much to you. A perusal of the online documentation is also advised.

CommonLook PDF won’t tag an untagged PDF; it works only on existing tagged PDF files. If your PDF isn’t tagged, use Adobe Acrobat’s “Add Tags” tool to automatically generate a tags tree. This is the starting-point for verification in either Adobe Acrobat or in CommonLook PDF.

Once your PDF is tagged you’re ready to use CommonLook PDF. Assuming you’ve installed and activated the software already, you’ll find a “CommonLook PDF” option under the “Plug-ins” menu. Below that option you’ll find the CommonLook PDF main menu offering various options. The menus are only available when a tagged PDF is open in Acrobat.

Screenshot of Plug-Ins, CommonLook PDF menuThe available options are:

  • Section 508 – Allows the user to test a specific checkpoint from the §1194.22 regulations on the current page or the whole document. This mode is useful when checking something specific, such as table structure, alt. text, or the use of color.
  • Current Document Results – Displays the Results dialog showing current checkpoint status.
  • Verify and Remediate – Provides the logical and physical views of each page along with a list of checkpoints to be addressed. This mode walks the user through each page showing only the pages with tags requiring review.
  • Logical Structure Editor –T his mode is similar to the Verify and Remediate mode, but does not automatically advance the user based on checkpoints status.
  • Continue Verification – If you’d stopped in the middle of a document, this option returns you to the place you’d left off.

In practice you’ll probably spend most of your time in the Verify and Remediate mode, but the other options have their uses, especially when dealing with tables that span pages.

Read the Manual! CommonLook PDF includes lots of features, and the interface, especially in the Verify and Remediate mode, can be intimidating. It is strongly recommended that the user take some time to read through the documentation and orient himself/herself with the tool before trying to use it.

How CommonLook PDF is Used

The following section is intended to offer a sense of how this tool may be used to review, report on and fix incorrectly tagged PDFs. It’s not meant as a tutorial on how to use the product or even as an example of how the product works. For more information, simply check out NetCentric’s documentation for CommonLook PDF on their website, or contact NetCentric directly.

Alt text for Figures (images)

Every accessibility validation workflow includes checking alternative text to ensure that it’s an adequate representation of the image with which it’s associated. In PDF, the images, charts, and other non-text graphics that convey content are tagged with “Figure” tags.

CommonLook PDF includes advanced functionality to help ensure alt. text is both present and meets accessibility guidelines, including a means of reporting a “Pass” or “Fail” for each tagged figure. This feature allows remediation information to be easily forwarded to document authors or supervisors for review or corrective action.

The simplest way to try this out is to first choose the “Section 508” option from the CommonLook PDF main menu, then select the (a) Text Tags checkpoint from the expandable list.

A window with two panels will open. In the bottom panel, you’ll see the first page of the PDF document you are evaluating that includes a tagged Figure. In the top panel you’ll see a table with a row for each figure on the page. It would be nice to have a side-by-side option for these panels, but the default configuration works fine as is.

screenshot of the text tags repair window

When you select a row in the top panel the corresponding content tagged as a figure is highlighted in the bottom window. You may then add or edit alternate text for that figure.

If appropriate (ie, if the selected image should be read as if it was text) you’d enter that text in the “Actual Text” column. Examples of cases when Actual Text is appropriate instead of Alt. Text include ligatures, an image used as a heading, and other cases where the content’s nature is textual (as opposed to a photo, say), but the means of its inclusion happens to be a JPEG, some paths (vector graphics), or whatever.

Select the "Pass" radio button for each image that meets your organization’s guidelines for alt. text, and either fix them or “Fail” the ones that don’t. If you add comments they’ll be included in the CommonLook Report you can generate when you’re done with your CommonLook PDF session.

This process is well implemented, with several advantages over Adobe Acrobat:

  1. CommonLook PDF includes the ability to fine-tune the basis for stopping the user to review alternative text quality via regular expressions.
  2. CommonLook PDF does not "pass" a PDF when all of the Figure tags have alt text present. Instead, it requires the user to look at each image that fails the automatic assessment, and either add appropriate alt text, confirm that existing alt text is appropriate, or change the Figure to an artifact, removing it from the tags tree.
  3. The pass/fail results for an individual PDF may be saved as an HTML report for QA and other purposes.

The Use of Color to Convey Information

Another good way to try out CommonLook PDF is the Color checkpoint, which you can find through the same menu item as the (a) Text Tags checkpoint, above.

screenshot of the color contrast comparison window

This checkpoint helps the user verify that color alone or color contrast isn't the only means of conveying information. The top panel shows the actual page while the lower panel shows a grayscale version of the same page. If information is missing when the two panels are compared without some other means of discerning the meaning then the page should be Failed. The resulting CommonLook Report may be used to document the decision and notify the author so they can provide a more accessible replacement.

Reading order

The order of content in a PDF can sometimes be very different from the tagged reading order. It’s preferable to have the content order be the same (to the extent possible) as the reading order because not every type of software uses PDF tags.

With Acrobat alone, ensuring reading order and content order are aligned can be a difficult and time-consuming process. CommonLook PDF provides precision tools in the Verify and Remediate and Logical Structure Editor modes which help you compare the actual PDF page with the reading order of containers and tags very quickly. Using CommonLook PDF’s advanced selection tool that makes it easy to know what you’re grabbing (something that can be very challenging in Acrobat), you can move and create tags, and reorder elements. Once done, saving the page causes the content order to align with the logical structure.

Depending on the complexity of graphics and text on the page, this can be a fairly straightforward step or very tricky (although less so than in Adobe Acrobat). Depending on the situation, it may be helpful to enable all of the visual cues available in the tags panel by choosing Borders and Glyphs from the View menu. The window should then look something like this:

screenshot of a portion of the logical structure editor tool

Although this is a powerful tool, the amount of information presented may be overwhelming. Be sure to play with turning the various view options on and off to get a feel for the value the offer in different circumstances. One tip: most of the time you won’t want to see Artifacts or Glyphs.

Many users come to CommonLook PDF after trying Acrobat’s Touch Up Reading Order Tool to edit the reading order of a page or assign a new tag to an element. Acrobat’s tool certainly has a much simpler interface than CommonLook PDF’s Logical Structure Editor. Depending on the simplicity of your PDF, Adobe’s tool may well be used to tag and reorder most content, but it struggles on complex pages because it lacks the powerful selection tools and keyboard shortcuts of CommonLook PDF.

From a testing point of view, unlike Acrobat, CommonLook PDF requires the user to verify the contents of each page as occurring in correct logical reading order before this checkpoint gets a Pass. While sometimes tedious, there’s no substitute. It’s just too easy for content to be mis-tagged or out of correct order, and document-level reviews won’t catch those sorts of errors.

Whether you use Acrobat’s TouchUp Reading Order Tool or CommonLook PDF, be sure to check the visual appearance when you’re done. While the precise selection tools in CommonLook PDF make it much less likely to reorder page content in a way that damages the visual appearance of the page than Acrobat, it’s not impossible.

Note PDF files may differ between the content order (as seen in Adobe’s Reflow mode) and the logical reading order (tags) as read by a screen reader. Since CommonLook PDF ensures that the two orders are aligned, if changes have been made with the Touch Up Reading Order tool it’s a good idea to at least open and save the document in the Logical Structure Editor. This has the effect of ensuring alignment between tags and content order (to the extent possible).

Table headers

Tagging tables in Acrobat hasn’t changed since Acrobat 9, especially for more complex tables. If your documents include lots of complicated tables, especially if they include cells that span rows or columns, or require linked headers, this plug-in can help make that process much easier.

CommonLook PDF’s Table Editor shows the logical structure represented by the table’s current tags. Three tabs toward the bottom of the window provide access to Table Properties, Cell Properties and the PDF’s page. The Cell Properties tab is where most of the action is.

screenshot of the window used to edit table properties

First, learn how to select more than one cell at a time. Use Shift + click to select all cells between two cells (as in a row or a column), or Control + click to select multiple individual cells. This feature makes an otherwise tedious process quite easy. If you have a table with headings across the top, you can create properly tagged headings in just a few steps:

  • Use Shift + click to select all of the cells across the top row.
  • Select Table Header Cell from the Cell Type dropdown list.
  • Select Column from the Scope dropdown list.

If the table includes row headers, follow the same steps selecting all the cells along the side and choosing Row from the Scope dropdown list.

More complex tables can require cells to be linked to headers via IDs rather than relying on the table’s structure. Here’s where CommonLook’s Table Editor really shines – it allows you to select header cells by clicking on them rather than knowing each TH cell’s ID. This may seem like a small thing but when you’re dealing with lots of complex tables, that feature, plus the ability to Append as well as Assign headers can save a great deal of time.

The Table Properties tab includes a “Check for Row Headers" checkbox, which causes CommonLook PDF to require row headers when verifying tables. Uncheck this if your table does not include row headers, then you’ll be able to Pass the table checkpoints on tables that don’t include row headers.

Fillable Forms

While HTML forms are an obvious choice for many forms, PDF files are increasingly popular as electronic fillable forms that may be submitted to a server but can also be readily saved for offline work while delivering high quality printed results.

CommonLook PDF evaluates forms in PDF files using several automated checks. If form elements aren’t tagged as such, or if tooltips are missing, or if radio buttons are present, the page is failed.

Like any other sort of content, form fields in PDF have to be tagged in correct logical reading order. CommonLook PDF’s Verify and Remediate mode allows you to add and verify tooltips and check and correct the tabbing order.

The application does not yet check to ensure that form labels printed on the page are grouped with the field object within the Form tag, or help you determine if the associated descriptions are appropriate.


NetCentric does not claim that CommonLook PDF is a fully automated solution for evaluating and repairing PDF files. The software automates as much of the evaluation process as possible, but it’s not especially simple to use. While it’s much improved beyond the original Acrobat plug-in we evaluated several years ago, CommonLook PDF’s strengths and weaknesses break down more-or-less as they did before, except that the user guide in version 4.2.4 is substantially improved!


  • Unlike Adobe Acrobat, CommonLook PDF helps evaluate a PDF document for accessibility and Section 508 compliance using a systematic, standards-based approach.
  • CommonLook PDF requires page-by-page validation of reading order, a critical check that Adobe Acrobat does not include. Since they have to review the reading order of each page as part of Passing the document, CommonLook PDF users are also more likely to ensure valid semantics (choice of tags) than those using Adobe Acrobat alone.
  • Several tasks, especially with respect to complex tables, are much easier using CommonLook PDF as compared to using Adobe Acrobat alone.
  • Detailed selection tools make it less likely that the page will be damaged due to content reordering.
  • The software includes several unique productivity tools including automated fixes for common problems such as text running together and incorrectly marked soft-hyphens (which causes them to be voiced), the ability to replace acronyms and abbreviations with better text for AT, and more.
  • CommonLook Clarity, NetCentric’s product that scans PDF files on websites and in folders, recognizes verification work performed with CommonLook PDF.


  • The software does not yet directly support accessibility standards beyond the 2001 Section 508 regulations such as PDF/UA and WCAG 2.0.
  • For full effectiveness, the learning curve with this tool can be quite steep; some tasks are more complex than they need to be.
  • The price might make it unrealistic for organizations with very limited funding, or those who do not work with PDF files on a regular basis.
  • Because the tool focuses specifically on Section 508 standards, an organization following other standards or guidelines will need to decide how the tool may be integrated into enforcement of their own guidelines.
  • This plug-in is only supported on Windows; there’s no version for the Mac.
  • Although it can work on files in any language, the software itself is only available in English.


While CommonLook PDF follows a systematic, checklist driven approach to Section 508 compliance, those regulations are seriously dated. We accept that they are the current rules, so NetCentric can’t be faulted for attending to them, but we’d love to see support for PDF/UA and, of course, WCAG 2.0. NetCentric says this is in the works for sometime in 2013.

It’s always best to make PDF files accessible as created, and avoid the need, to the extent possible for tools like Adobe Acrobat and CommonLook PDF to manage and quality-control tags. Even so, most people who could make well-tagged PDF files don’t; lots of existing PDF files aren’t tagged and need to be.

CommonLook PDF may be overkill if:

  • The upfront cost is prohibitive.
  • You rarely need to check PDF files for accessibility features.
  • Your files only require simple repairs that are easy to do in Adobe Acrobat.
  • Your files can be created accessible from the beginning.
  • Your documents rarely include complex tables.
  • Your documents have simple layouts, without layered graphics.
  • You don’t feel the need to ensure reading order and content order are aligned.

CommonLook PDF may be perfect for you if:

  • You want a clearly-defined, systematic process for verifying accessibility.
  • Labor costs are high, and you need to tag a large number of PDF files.
  • Your PDF files have numbers of complex tables.
  • You do not have access to the source files.
  • You need to document accessibility efforts with detailed actionable reports.
  • The nature of your content is such that Acrobat’s selection tools are inefficient.
  • You are planning to use CommonLook Clarity to monitor your website’s PDFs.

Despite its weaknesses, CommonLook PDF is the most complete solution for PDF accessibility we’re aware of at this time. If you are looking for an enterprise-level PDF accessibility tool, and if you can handle the up-front cost, both for the software and the learning curve, CommonLook PDF can substantially improve both efficiency and quality in producing well-tagged and accessible PDF files.

  • Software evaluated: CommonLook PDF 4.2.4
  • Vendor: NetCentric Technologies
  • Website:
  • Price: $1,299 (list) for single user license. Substantial discounts are available for volume purchases.