1 2 Previous Next 25 Replies Latest reply on Jun 10, 2019 7:57 AM by Catherine Tsouvaltsidis Go to original post
      • 15. Re: FAQ: Accessibility
        Jeffrey Lam

        Thanks Kyle! This is very comprehensive! Definitely a must for those questions related to conformity.

        • 16. Re: FAQ: Accessibility

          Hi Kyle,


          Thank you very much for sharing information about designing accessible dashboards!  My state agency has been working with our web team on redesigning our dashboards to ensure that they meet the Section 508 requirements.  There have been some challenges, and I hope you will be able to give me some guidance.


          One challenge I have is the table below.  The table uses a black and red color to show increase and decrease from a prior year change.  My web team suggested that we include a shape so that color is not the only distinguishable mark on the table as an indicator of the increase/decrease information.  The tooltip will also provide the percent change information.  From your experience, is the red and black colors distinguishable enough in the table?  There aren't many marks but will this table provide a disservice for individuals with color contrast difficulties?



          • 17. Re: FAQ: Accessibility
            Kyle Gupton

            Hi there -


            You're very welcome! There are two separate issues here regarding conformance with the WCAG 2.0 Level AA standards (which is what I always use as the reference guidelines for accessibility and is what the Revised Section 508 also uses for web-based software):


            1. Use of Color (Guideline 1.4.1): This guideline states that color should not be the only visual means of conveying information. This guideline exists to account for the many variants of color-blindness. Red-green colorblindness is the most common, but there are others. Note that the Tableau Color Blind color palette is designed for red-green colorblindness, but its use does not satisfy this WCAG guideline. Using a tooltip to provide additional information will cause other accessibility issues in that tooltips are not yet usable with a keyboard or assistive technology. One option to conform to this guideline is to use text size in addition to color to note "special" values.


            2. Color Contrast (Guideline 1.4.3): The red text does not have sufficient contrast (at least 4.5:1) with the background (either the gray or the white). You can check the contrast ratio using a free tool like the Colour Contrast Analyser. To conform to this guideline, you'll need to choose a text color with more contrast against gray/white.


            I hope this helps!



            • 18. Re: FAQ: Accessibility

              Hi Kyle,


              Yes, the information helps!  Thank you for the size suggestion, I will try this option.  Regarding the color contrast, the red text (#AE123A) on white (#FFFFFF) and gray (#f5f5f5) does pass the contrast checker (I checked with this website).  That is the reason why I thought the red and black will have enough color distinction without having to include a shape in the table.  Despite possibly having distinct color contrast, it seems that #1 (Use of Color) is stating that anytime we use color to convey a information, there has to be another way to convey that same information by shape and size, correct?

              • 19. Re: FAQ: Accessibility
                Kyle Gupton

                Glad to hear that the red color does meet the contrast requirements. I was using the Colour Contrast Analyser color picker and must not have gotten the darkest color in the anti-aliased font when I sampled it.


                Yes, when you use color to convey information, there must be some other way to convey that same information. Shape and size are often good choices, but a text label can be appropriate depending on the situation. A good example is when the color of a bar in a bar chart is encoding a measure, a label displaying the measure value is a good alternative.



                • 20. Re: FAQ: Accessibility
                  Tamara Augsten

                  Hi Kyle,


                  Thank you for this amazing resource. I work for municipal government in Ontario and need to get the tableau dashboards/stories to meet AODA requirements or WCAG 2.0 A. I am a little bit unclear about this but from reading it seems that Tableau Stories are inherently inaccessible due to their inability to be tabbed through. Is this correct? If so, do you know if a solution to this could be to provide the underlying data as a screen readable table below the story on the website?


                  For context, I was about to start working on making a story like this one accessible (colours, contrast, proper descriptions, etc.) as well as to create an iPhone layout. It looks like the story method may not be the right way to go about either of these things... Tableau Public


                  Let me know if you have any thoughts or experience with Tableau Stories and accessibility.





                  • 21. Re: FAQ: Accessibility
                    Kyle Gupton

                    Hi Tamara -


                    Indeed Stories in Tableau are not currently keyboard navigable, which is a big part of accessibility. If you use Stories in your workbook, then it won't meet WCAG 2.0 Guideline 2.1: Make all functionality available from the keyboard.


                    Providing the raw data in a table below the story will make the data available, but it doesn't solve the lack of keyboard accessibility. I wouldn't recommend it as a solution. At this point, if accessibility is a requirement, then I suggest avoiding the use of Stories. We know about this limitation, but I don't have a timeframe for when it might be resolved.



                    • 22. Re: FAQ: Accessibility

                      Hi Kyle,


                      Since all documents on my agency's website have to meet the WCAG requirements, that will include Tableau's downloaded PDFs.  However, the PDFs are not accessible.  Is there a way to make them accessible?



                      • 23. Re: FAQ: Accessibility
                        Kyle Gupton

                        Hi -


                        Unfortunately there isn't a way to make our PDFs accessible in Tableau. I'm not sure what options exist in Adobe Acrobat Pro for improving the accessibility, but generally Tableau PDFs don't actually include the data, so there's only so far you could go.


                        We do hear this request from time to time, but not that frequently compared to other accessibility needs. I suggest creating an Idea on the Ideas Forum for this one.



                        • 24. Re: FAQ: Accessibility

                          Thanks, Kyle!  After doing a bit more research, I found that the idea has already been posted on the Ideas Forum: https://community.tableau.com/ideas/8548.  =)


                          I strongly encourage everyone to vote for this idea, especially if your external users are downloading PDFs from your Tableau dashboards!

                          • 25. Re: FAQ: Accessibility
                            Catherine Tsouvaltsidis

                            Hi Kyle,


                            I have been working on some custom color palettes for the community. The color palettes have been formed based on the color palette information found at http://mkweb.bcgsc.ca/colorblind/ for deuteranopia, protanopia, and tritanopia. Only colors which have passed the Color Contrast Analyzer with AA standards are included.


                            color blind palettes.png


                            For knowledge, I have only transformed those in the grey box and included if they should be used with a white or black background.


                            Use the following instructions to make / modify your preferences file: https://onlinehelp.tableau.com/current/pro/desktop/en-us/formatting_create_custom_colors.htm#about-the-preferences-file


                            Thanks for all your hard work championing Accessibility!


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