Alt Tags in: Word 2007, PowerPoint 2007, PDFs, MyAberdeen
Provide appropriate text equivalents for images, graphs and charts
The use of Alt Tags
Images included in eLearning materials often provide essential visual information or clues to concepts or ideas. For visually impaired students who may be using screen readers users, it is possible to provide a textual representation of the image by including alternative text, commonly referred to as Alt tags. If Alt text is not provided, all the user will hear from the text reader is "Image", which effectively tells them that there is an image on the page but not what it is. Too much, or irrelevant, information in an alt tag will equally frustrate and slow down the text reader user - they're busy people too! For images that are included purely for decorative purposes it is recommended that two sets of double parenthesis are used in the Alt tag field (Alt=""""), most of the commonly used text readers will then ignore the image. For further advice see WebAim’s article on the Appropriate Use of Alternative Text.
By default Word 2007 uses the file name of the image, e.g. 'IMG_2033.jpg', as an Alt tag, which for screen reader users is both annoying and frustrating as this tells them nothing and will slow their browsing down considerably. For images which add no further information than the associated text it is important to use empty parenthesis i.e. alt="" so that screen readers ignore the image and move on to the next item. As with 'Styles', adding Alt tags has not become any more intuitive with subsequent editions of Word. Full guidance is provided by WebAim's Word article and TechDis's Accessibility Essentials series. Once Alt tags have been inserted on images in Word 2007, they automatically transfer across to PDF documents if using Acrobat.
In addition to the more obvious using appropriate font sizes, colours and sensible slide transitions the most important things for accessibility in PowerPoint are Styles and Alt tags.
- Using any of the in-built templates will ensure Styles are used appropriately
- Alt tags for images can be added in a similar manner to those in Word. In PowerPoint 2007 right click on the image, select image size and position and enter alternative text within the Alt text tab dialogue box
For more detailed advice see: http://webaim.org/techniques/powerpoint/. For advice on using PowerPoint effectively see http://www.jisctechdis.ac.uk/AccessibilityEssentials/2007/AE3/index.html
Unless Adobe Acrobat Professional is used to create PDFs it is highly unlikely that the resultant files will be accessible (see Rich Media, PDF section). If a PDF was created in Adobe Acrobat Professional from a Word document in which Alt tags were added to images, these will be carried across to the PDF. If Alt tags were not included in the original document they will need to be added using Acrobat Professional.
In the Tools menu, select Advanced Editing, Touch Up Reading Order
From the Touch up Reading order panel select Show Order Panel, select the image without the Alternative next and right click on it and select Edit Alternate Text.
Type the Alt tag in the Alternate Text window
Click OK and the Alternate Text appears with the image
When including images indirectly in Blackboard Learn 9.1 an empty Alt tag alt=”” is automatically generated. This is ideal for when the image provides no additional information to what has already provided in any accompanying text. If the image does provide additional information which needs to be included for screen reader users the Alt tag must be added by…. (instructions needed!)
For tips and advice on good practice see Techdis Accessibility Essentials 3 - Creating Transitions and Animations within Microsoft PowerPoint and Techdis Accessibility Essentials 3 - Basic Good Practice for Accessibility within Microsoft PowerPoint.