Science1 publisherNot yet confirmed elsewhere3 min readPublished
Light readings from Lord's suggest the red ball is fairer to colour-blind cricketers
Australian, British and Dutch researchers model the pink ball as harder to see for colour-blind cricketers, who are about 9% of male Australian grade players. The finding rests on light measurements with no players tested, and follows the ICC's June approval of pink-ball trials in bad-light Tests.
The Scientist · Science desk
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What happened
- In the model, deuteranomaly makes the pink ball harder to see against the pitch when batting, and protanomaly makes it harder against crowd or grass when fielding.
- A few combinations of ball colour, ball age, background and time of day may actually favour players with colour vision deficiency.
- Former Australian Test opener Chris Rogers, who has red-green deficiency, lost sight of a green-stitched pink ball against a black sight screen in an early match in Abu Dhabi.
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Why it matters
- decision The trial needs both teams' prior consent, so a side with a colour-blind batter or fielder now has a published reason to weigh before agreeing to a pink ball in failing light.
- exposure If the grade-cricket rate holds at Test level, about 87% of men's Tests would include at least one player facing the contrast deficits the model predicts.
- constraint Without on-field or injury data, the study cannot tell the ICC whether lower contrast changes results or injury risk, so any review of the trial would need player testing under dusk light.
For every pairing of ball, time of day and background, the researchers computed the ball's luminance contrast twice: once for a typical observer and once for observers with each form of colour vision deficiency (CVD) [7]. The typical observer is the control. Every case used the same lab and Lord's measurements [6], so any gap between observers comes from the eye being modelled. The study is published in Sports Medicine [8]. Nobody in it faced a delivery. Luke Wilkins, who studies visual, perceptual and cognitive skills in sport at La Trobe University [18], said: "Our study did not measure injuries or on-field performance, but it identifies situations where visibility could be problematic and where further investigation is needed." [5]
Wilkins described the output as conditional. "Our computer modeling suggests that different types of CVD create different challenges for seeing a cricket ball. These challenges depend on the ball's color and condition, the background and the time of day," he said [10]. The press summary gives the direction of each effect but not the contrast values, so the size of the gaps cannot be judged from it. His overall verdict favours the red ball: "There is no single ball that provides the best visibility for everyone in every situation. However, on balance, our findings suggest that the red ball provides more consistent and equitable visibility across players and conditions." [1]
He treated safety and fairness as one problem. "Cricket balls are hard and travel very fast, so anything that makes them harder to see warrants attention," he said. "We also need to consider whether the choice of ball places some players at a greater disadvantage than others." [17]
The 9% figure comes from earlier research on male Australian grade-level cricketers [4]. Test squads are a different population. At that rate a side of 11 would include about one player with CVD on average [20]. Across the 22 players in a men's Test, the chance that at least one has CVD would be about 87%, if each player carried the grade-cricket rate independently [21].
Chris Rogers's experience fits the model, though it is one player's account. Of that early pink-ball match in Abu Dhabi, he said: "I was facing an offspinner and I couldn't pick the ball up in the sight screen." He added: "For me it looked like dark on dark." [13] The sight screen was later changed to white and the seams to black, and Rogers retired soon after [14]. Commentating on day-night matches, he still struggled to follow the line of the ball through a dark shadow [14]. The red ball gave him trouble too, in the air against the crowd or dark seats while he was fielding. He took to sunglasses with red and yellow lenses, which he said made colours "pop" [15]. Wilkins said the red ball has problems of its own, but from a visibility standpoint it is likely better in more scenarios and fairer across players [2].
The pink ball has been used in day-night cricket for more than a decade [19]. The June decision would take it into Tests expected to be hit by bad light, provided both teams agree in advance [3]. I'd expect the most useful next experiment to put players with deuteranomaly and protanomaly in front of red and pink balls at dusk, against the backgrounds measured at Lord's. Wilkins spoke to the governing body directly: "Our findings give the ICC reason to review when and how the pink ball is used, particularly before expanding its use to address poor light." [16]
What to watch
- Whether any pair of Test teams agrees to use the pink ball under the ICC's bad-light trial, and whether the ICC revisits the terms as Wilkins urged.
- Prevalence figures for colour vision deficiency in international squads, which would replace the 9% estimate drawn from Australian grade cricket.