Introduction to Writing Descriptions for Complex Content

This resource introduces the concept of long/extended descriptions, and provides a general discussion of how to approach and develop them.

  • Subject(s):

    Image Descriptions

  • Resource Type(s):

    Standards and Best Practices

  • Audience:


Suggested Prerequisite

Before reading this, you might want to read:

Complex images often require long descriptions, and are important for accessibility. When they are included, readers with print disabilities are able to fully understand a book, and are able to have an equitable reading experience. Creating good long descriptions will take some practice, but including them will mean that your books are incredibly inclusive, and they are able to be used by all readers.

A complex image is any image that contains complex information or data. Common examples are Maps, Graphs, and Charts. Nearly all complex images require long descriptions.A Long Description is a detailed text description of an image that can be several paragraphs long and/or may contain other elements such as tables and lists. This technique is generally used for complex images where spatial information needs to be conveyed to the reader such as maps, graphs, and diagrams. Sometimes called extended descriptions, these descriptions are too long and complex for alt-text, and must be provided somewhere within the text of a book.

The Importance of Long Descriptions

Depending on the complexity of the image and the information it conveys, you will need to decide if an image requires a long description. Pay close attention to the context of an image because it is possible that it will be fully described and explained in the paragraphs that are close to the image. You could save yourself a lot of time, just by scanning/skimming/reviewing the context surrounding the image! If the image and the concept that the image is conveying is fully described in the text, you may not need to write a long description. Instead, simply provide short alt-text, and include a line that says “The information demonstrated in this image/graph/map is fully described in the text.”

When a long description is needed, a short description should still be included in the alt-text of the image element. The alt-text should provide enough information for the reader to decide if they need to read the long description.

Other Approaches

Writing long descriptions for complex images will help readers learn and understand the information. But, long descriptions are not the only way to share visual information in non-visual ways.

Images can be separately produced as a tactile graphic using a variety of techniques that place a raised image on paper or render it as a tactile audio display (tactile graphic accompanied by audio description). As mentioned above, MathML can be used to make accessible both the structure and the content of mathematical and chemical notations. Certain chemistry images can also use chemical notation braille code, Scalable Vector Graphics, and chemical file formats. Sonification is a modality that provides non-speech audio to represent a graphed equation. Haptics and Three-dimensional models can be made for the student to touch. MusicXML, MIDI, and standard audio files can be used to access musical notations. Exploring these different modalities may inspire you to enhance the accessibility of your books in different ways, and we encourage you to explore them!

Next Steps


Understanding the Importance of Image Descriptions

Introduction to Image Descriptions

Including image descriptions in your ebooks and digital content hugely increases accessibility because it ensures that all readers have access to the same content. This Introduction discusses the importance of image descriptions – to your…

Subject(s): Image Descriptions
Resource Type(s): Foundations and Rationale

Determining who Can/Should be Tasked with Writing Image Descriptions

Who Should Create Image Descriptions

This resource discusses the options you might have for image description creators/authors. There are many different people that can potentially do this work, and deciding on a person or group is an important step!

Subject(s): Image Descriptions, Strategic Planning
Resource Type(s): Standards and Best Practices

Reviewing Image Descriptions

Guide for Reviewing Image Descriptions

This guide shares a short checklist of items to review when reading or editing image descriptions. Whether you wrote them yourself, or someone else wrote them, this guide will help ensure the quality of descriptions.

Subject(s): Digital Marketing, Ebook Production, Image Descriptions, Website Accessibility
Resource Type(s): Checklist, Standards and Best Practices

Writing Descriptions for Digital Media

Introduction to Writing Alt-text for Digital Media (other than ebooks)

Images used on websites, social media, and other non-book content need image descriptions. The writing guidelines are mostly the same, but there are a few additional things to consider. This Introduction document looks at these,…

Subject(s): Digital Marketing, Image Descriptions
Resource Type(s): Checklist

External Links to More Information

Writing image descriptions for graphs

This post discusses writing alt text for different types of graphs. It includes examples of a pie chart, bar graph, and line graph.

Write good Alt Text to describe images

This page from Harvard College gives tips for writing image descriptions. It covers the importance of providing context, and has several examples. It discusses the specific cases of graphs and images containing text. Links to other pages on the Harvard site and external resources are given for more information.

Guide to Image Descriptions

A thorough introduction to image descriptions; it discusses: the importance of image descriptions, workflow considerations, and terminology; it also provides some technical guidance and code samples, and of course provides detailed image description guidelines, with examples!

Poet Image Description Tool

Developed by The DIAGRAM Center, the Poet image description tool is an open-source, web-based tool for creating and providing guidelines to writing image descriptions for images in existing books. Some people may find it a useful tool!

Image Description

This page from the Diagram Center has several resources about image descriptions: the Poet image description training tool, diagram image description guidelines, a sample book, some archived presentations, description templates for common graphics, and some survey results documenting the value of image descriptions.

Describing Images in Publications

An archived webinar from the DAISY Consortium on June 17, 2020 which gives an overview of image description. It has information about the Poet image description tool from the DIAGRAM center, tips and examples for writing descriptions, some comments on automatically generated descriptions (can identify the category but descriptions are not yet adequate) and some publisher processes for adding them. DAISY webinar archives include the video of the webinar, a written summary, presentation slides, a transcript, and links to further resources.

The Art and Science of Describing Images

An archived webinar from the DAISY Consortium on July 22, 2020 on the topic of image description. It discusses several types of diagram-style images and how to describe them. Most are different types of charts. DAISY webinar archives include the video of the webinar, a written summary, presentation slides, a transcript, and links to further resources.

The Art and Science of Describing Images-Part 2

An archive of a webinar in the series on describing images from the DAISY Consortium given on December 2, 2020. It covers maps, timelines and bar charts. DAISY webinar archives include the video of the webinar, a written summary, presentation slides, a transcript, and links to further resources.

The Art and Science of Describing images-Part 3

An archive of a webinar in the series on describing images from the DAISY Consortium on February 10, 2021. This covers artwork, anatomy and assessment images.

Image Description: Advice From the Front Lines

This post gives approaches by four publishers on how they produce image descriptions. Some do it in house, and others use a vendor or the author. More complex images can benefit from someone with training in image description and knowledge of the subject.

How to Write an Image Description

This article gives ideas for writing image descriptions. It uses an “object-action-context” order to provide details in a logical way. It also includes some more suggestions for when to describe race and gender, and breaking more complex image descriptions into sections.

Content Source Acknowledgement Guide to Image Descriptions

Diagram Center: Accessible Image Sample Book