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Colour and communication in geoscience

Colour is a prevailing way to communicate geological concepts, so how can such information be conveyed to those who are colour blind? Ryan Wakeling and Torquil MacLeod explore opportunities to enhance inclusivity

Words by Ryan Wakeling and Torquil MacLeod
1 March 2023

Globally, colour vision deficiency (CVD) or colour blindness affects approximately 1 in 12 men (8%) and 1 in 200 women (0.5%). Despite this prevalence, through our own experiences (Ryan has CVD himself and Torquil has close family members with CVD), we have found that colour vision deficiencies can go completely unnoticed, especially in the workplace. Here we outline some useful tools to improve our visual outputs.

What is CVD?

Colour vision deficiency (CVD) occurs when the colour-sensitive cells in the eyes, called cones, are either missing or do not function as they should. In most cases, CVD is caused by a genetic fault, although CVD may also develop because of underlying health conditions, as a side effect of medication, or through exposure to harmful chemicals.

There are several types of CVD, including:
1) Protanopia, difficulty detecting red light; 2) Deuteranopia, difficulty detecting green light; and 3) Tritanopia, difficulty detecting blue light. Those affected by CVD may exhibit a combination of traits from more than one type.

Eight Ishihara charts for testing colour blindness

Eight Ishihara charts for testing colour blindness, Europe, 1917-1959 (Credit: Shinobu Ishihara and the Science Museum, London, Attribution 4.0 International (CC BY 4.0), via Wikimedia Commons)

Testing for CVD

The Ishihara test, first published in 1917 by Shinobu Ishihara, is a widely used colour vision test, originally designed for the purpose of detecting red-green colour deficiencies. The test involves several pseudoisochromatic plates, each with a series of coloured dots depicting a number or a line the subject must trace. Even for Torquil, who does not have CVD, the colour combinations used in the Ishihara test are hard to comprehend, but, for those affected by CVD like Ryan, some are completely unreadable. Other colour vision deficiency tests include the Farnsworth–Munsell 100 hue (D-15) test and the Farnsworth Lantern Test.

From this, it is apparent that shades, textures, and colour combinations are an important consideration when presenting data to others. Graphics are commonly used in the geology and engineering industry to display data outputs but, with approximately three million colour blind people in the UK, many colleagues, clients, and stakeholders may find it difficult to understand these outputs.

CVD and careers

CVD has the potential to dictate many career paths. Ryan dreamt of becoming a pilot from a very young age; that swiftly changed after discovering he had CVD. Careers such as aviation, engineering, medicine, and military forces all involve or rely on correct colour identification. While our experience is largely from within the engineering and construction industry, our clients and the end users of our designs and illustrations represent a diverse cross-section of society.

Our interactions with others and exposure to different documents and drawings produced by colleagues reveal a lack of understanding of the impact of CVD and how it may limit an individual’s ability to understand information. This often manifests as poorly chosen colour schemes for geological maps and technical drawings, signage on sites and in offices, and logos and symbols, which would lead those with CVD to misinterpret key information.

Colour and ground engineering

Since they were first produced, it has been standard practice to use colour to denote different rock and soil types on geological maps. Figure 1 depicts how those with CVD may perceive the colours used on geological maps and illustrates how variable the perception of some of those colours may be, even with the presence of a legend.

Colour is essential for conveying information in the ground engineering industry. Colour is used to distinguish between rock types on ground models and geological maps, identify buried services on drawings, highlight specific hazards on plans, denote quantities on graphs, identify minerals in thin section – the list goes on.

Figure 1: William Smith’s 1815 geological map viewed (clockwise from top left) by someone with normal vision; protanopia (red-blind); deuteranopia (green-blind); tritanopia (blue-blind). (Credit: The Geological Society of London, UK. Archive ref: LDGSL/22).

The Atkins survey

In November 2022, we surveyed staff members in the Ground Engineering & Tunnelling department of Atkins, UK, obtaining 91 responses from over 300 staff members. Our results from these Atkins employees revealed that awareness and understanding of CVD within the ground engineering industry may be limited.

When asked ‘Have you ever been tested for colour blindness?’, 50% of respondents (46 out of 91) replied ‘No’, which may indicate that some individuals do not know whether they suffer from CVD. Considering the statistical occurrence of CVD globally, it may be that more than 20 of our ground engineering and tunnelling colleagues are affected by CVD. Across the broader company and ground engineering industry in general there could be a significant number of employees (many thousands) who are struggling or failing to identify key information.

Of those that were tested, 29% said the test was carried out during a school or standard eye test (or similar), while 12.5% said the test was carried out as part of a medical examination relating to training courses required for work on specific sites. This implies that CVD is generally only detected whilst testing for other sight characteristics and that only a small proportion of people – those requiring specific medical examinations – may be tested for CVD in our industry.

When asked ‘Have you ever had an experience yourself or with a fellow colleague in the ground engineering industry, who is colour blind? ‘, only a third (30 out of 91) responded ‘Yes’, implying limited experience catering to those with CVD.

Most individuals only became aware of CVD on a case-by-case basis, when a colleague had trouble seeing colours presented in a specific piece of work

Comments on the survey showed that most individuals only became aware of CVD on a case-by-case basis, when a colleague had trouble seeing colours presented in a specific piece of work. This suggests that accommodations for those with CVD within the industry may be predominantly reactive rather than proactive; making changes where required, rather than incorporating accessibility within designs and workflows from the start. The findings of the survey support our personal experience of the limited awareness of CVD and the issues faced by those with CVD. 

Tools to aid accessibility

At Atkins, the Neurodiversity Network and ENABLE Network are two initiatives that focus on educating and supporting employees by sharing experiences and resources related to conditions, visible or not, such as CVD.

As we have investigated improving our designs and outputs, we found many valuable tools to increase accessibility. They can be used to plan the appearance of outputs in advance and to check the accessibility of existing visual outputs. These tools include:

  • Microsoft Office Check Accessibility Tool. Found under the Review tab, this tool highlights aspects of a document that could be amended to improve accessibility.
  • Foxit PDF Editor Accessibility Checker. Similar to the above, this tool reports on the accessibility of PDF documents.
  • Web-based tools, such as Coblis (Color Blindness Simulator; www.color-blindness.com/coblis-color-blindness-simulator/), which allows users to upload images and screenshots and visualise how it would appear to people with CVD.
  • Mobile phone apps, such as Chromatic Vision Simulator that allow you to view images through your phone’s camera, as if through the eyes of an individual with different forms of CVD.

Simple techniques, which don’t require the use of an app or other tool, can be the most effective for increasing accessibility for individuals with CVD, for example:

  • Use a variety of methods, other than different colours, to convey information in images, such as different symbols or patterns.
  • When images are used in documents, include a stand-alone text description of the image that explains what the image is conveying.
  • Highlight important features in images with higher contrast.
  • Avoid using red and green or other colour combinations that are commonly difficult for those with CVD to distinguish between. 

Ryan Wakeling

Engineering Geologist, Atkins (a member of the SNC-Lavalin Group), Epsom, UK.

Torquil MacLeod

Associate Geologist, Atkins (a member of the SNC-Lavalin Group), Glasgow, UK.

Further reading

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