Difficulty accessing alternative text for visual items (difficulty accessing an item)

Help-Seeking Situation: Difficulty accessing alternative text for visual items (difficulty accessing an item)

 

Relative Importance:

 

Definition: It is a physical situation related to an inability to perceive text for an information resource, item, or content (e.g. image, photograph, drawing, illustration, newspaper, map) that is not presented in textual format in the digital library.

 

Factor(s):

 

  • No alternative text
  • Lack of description

 

 

Guideline or Design Recommendation

  1. Provide concise and correct alternative text for a visual item.
  2. Enable transcript of scanned visual items.

 

Rationale and Objective: DLs contain a variety of heterogeneous content (e.g., images, maps, newspapers, photos, books). Due to this variety and its presentation, it is difficult for screen reader users to access alternative text for resources that are typically scanned in and may not have alternative text available or transcript activated within the DL. Alternative text or transcript provides a textual alternative to non-text content in DL web pages. With current technology, computers and screen readers cannot analyze visual items and describe them unless the image is OCR’d. Alternative text or transcript is needed, which is read by screen readers. The content and function of the visual item should be described according to the DL web page context, or the user is unable to understand the item because the context in the DL web page might be different, even if the item is the same in several web pages. The word selection should be considered for the context. A description of visual items can be indexed by search engines and be used for a search. Alternative text or transcript affects the decision of whether a user is capable of reading the details of visual items. It can be helpful in accessing information quickly because some visual items take time for loading.

 

Techniques, Methods, and Features

Techniques and Methods

  • Add descriptive statement indicating the nature of the visual item as an alternative text.
  • Metadata descriptor of the visual item should specify the item type in search results for screen reader interpretation.
  • The metadata terminology for descriptions should be easy and clear for a user’s understanding.
  • A context-sensitive description is recommended, considering the function of the visual item more than the content itself if the item has a role in the webpage.
  • Avoid redundancy with information provided in other sections.
  • The content of the visual item is presented in the surrounding section, an alternative text might be needed.
  • Non-informative decorative images, which are not meaningful to context, should have empty alt text.
  • Informative Images and visual items should have descriptive alt text.

 

Features

 

  • Alt attribute

 

  • Detailed metadata
  • Detailed description
  • Context-sensitive description
  • Easy terminology

Examples:

  • Metadata descriptor of DL item format appears as “Portrait of Martin Luther King Jr., civil rights activist”
  • Enabled transcript feature that provides a text-based representation of the visual content

 

 

  • Clear and detailed summary description of visual item, with a clear header to quickly access the information

 

Related Resources:

Fulton, G. (2017). Accessibility Basics: Designing for Visual Impairment. Retrieved from https://webdesign.tutsplus.com/articles/accessibility-basics-designing-for-visual-impairment–cms-27634

 

Lazar, J., Allen, A., Kleinman, J., & Malarkey, C. (2007). What Frustrates Screen Reader

Users on the Web: A Study of 100 Blind Users. International Journal of Human-Computer Interaction, 22(3), 247-269.

Understanding WCAG 2.0: A guide to understanding and implementing WCAG 2.0. Retrieved from https://www.w3.org/TR/UNDERSTANDING-WCAG20/text-equiv-all.html

WCAG 2.0 Guideline 1.1: Text-alternatives https://www.w3.org/TR/WCAG20/#text-equiv

WebAIM(2017), Alternative text, https://webaim.org/techniques/alttext/

Xie, I., Babu, R., Castillo, M. D. and Han, H. (2017), Identification of factors associated with blind

users’ help-seeking situations in interacting with digital libraries. Journal of the

Association for Information Science and Technology. doi:10.1002/asi.23982

 

 

See Also: Help-seeking Situations > Difficulty accessing information > Factors > System design > No alternative Text

 

Help-seeking Situations > Difficulty accessing information > Factors > System design > Lack of Description

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