Making roller derby accessible for people with colour vision deficiencies

What is colour vision deficiency

Colour vision deficiency (often referred to as ‘colour-blindness’) affects a significant proportion of the population. In Europe the most common form of it affects 1 in 12 people with a single X chromosome and 1 in 200 people with two X chromosomes (

Despite this prevalence, many aspects of society are not made accessible to colour-blind individuals.

Exactly how colour-blindness affects someone varies from individual to individual. By far the most common form is red-green colour blindness which means that the person has abnormal red or green cones in their retina. The impact this can have ranges from a person struggling to tell the difference between a reddish-brown and a greenish-brown through to a person being completely unable to see one of the colours.


Describing colour-blindness is very hard to do to someone without it. It’s incredibly hard for a person with normal colour vision to imagine not being able to do something which comes so naturally.

NOTE: Please remember that with all these examples the fact that you’re viewing it on a screen and not in real life will alter the colour display.

The example I often use when trying to describe my personal experience of colour-blindness is that I can’t play snooker. The moment the brown ball ends up amongst the reds I can’t tell where it is anymore because the colours are just too similar for me. The image below is a simulation of how I view snooker balls – it’s not perfect but I hope it will give you an idea.

Picture of a standard set of snooker balls. The image on the left shows the original colours and the picture on the right shows a simulation of viewing the balls with colour vision deficiency.

Original image by barfisch – Own work, CC BY-SA 3.0, Link

Another example is the standard tests used to diagnose colour-blindness: the Ishihara plates. In the image below, people with normal colour vision are expected to see the number 74 whereas those with red-green colour vision deficiencies are expected to see 21.

Further examples can be found at

Impact in roller derby

So, let’s get to the meat of this – exactly what impact does colour-blindness have in roller derby? I’m going to approach this as an official as that’s my only real experience of the sport but remember that most of these issues are likely to impact other roles connected to the sport as well.


The biggest issue I’ve come across is the colour of people’s numbers. It is very common for skaters to choose to put red numbers on a black (or other dark colour) background. This isn’t particularly easy to see for anyone but can be problematic for those with red-cone deficiency.

Take this image below – with full colour vision it appears to contrast quite well. (Apologies to any skaters with the number 123, this isn’t picking on you I just had to choose a number).

123 in red text on a black background

Now I’ll apply a filter to simulate colour-blindness.

The above image with the red component reduced

This number is obviously a lot harder to see. Now remember that people will be trying to read this number as it moves around on a skater’s back or arm and hopefully you’ll be able to imagine how hard that can be.

Shirt colours

The other problem which I’ve come across on a few occasions is the colour of the kit worn by each team being too similar. The rules state that the teams must wear contrasting kits but the interpretation of contrasting can differ and those with full colour vision sometimes don’t consider how the kits may look to those with colour-blindness.

I’ve only ever had one kit combination where I’ve been completely unable to tell two teams apart. This was green versus grey and the players’ sweat had turned both colours into a dark greenish-grey to my eyes. Fortunately I was an OPR and this was Sur5al so I stepped out for a few jams and all was fine. However, if this had been a full length game then I would have likely had to withdraw from the crew.

The more common issue I have is where the team colours are slightly similar but different enough to be identifiable (for instance green and black). This is all fine before the game but once skaters start moving things like pack definition become very hard.

For pack definition I generally rely a lot on my peripheral vision where colour vision is worse. However, when the colours are closer I have to use my central vision more which increases the mental load of pack definition and notably reduces my ability to focus on other areas of the game.

What can be done to improve accessibility

There are a hundred tools out there for simulating colour-blindness that you might be able to use to determine if kits are sufficiently readable. However, none of them can simulate it perfectly and there’s a much easier way to be sure: luminance.

Colour-blindness impacts how hues are observed but how dark or light something is isn’t impacted. So, if two things are of a completely different brightness then they’ll always be visible regardless of colour vision.

The image below depicts a particularly hard number for me to see – red on a dark coloured background. (Again, these colours chosen for difficulty not to single out any team or skater).

Red 123 on a dark turquoise background

If we convert this to greyscale then we get the following:

The above image converted to greyscale

Now the number in this image is definitely visible, but I wouldn’t describe it as highly contrasting which is what we want. So, let’s look at a colour which could make this a lot better.

Light yellow 123 on a dark turquoise background

Whether or not yellow is a particularly aesthetically pleasing colour to go for in this case, it does make it a lot clearer and I wanted to choose a colour rather than just plain white to show that it can be something more interesting. When converting this to greyscale we get the following:

The above image converted to greyscale

This is obviously much more contrasting and could easily be seen by someone even if they had complete colour-blindness.

The other option is to use a highly contrasting border around the number. This way the desired colours can be kept but it still makes it possible for colour-deficient people to see.


Roller derby is a wonderfully inclusive sport but more could be done to improve accessibility for people with colour vision deficiencies whatever their role in the sport.

The simplest steps to take to ensure that the sport is accessible are for teams to ensure that their numbers have a highly contrasting luminance with the rest of their kit; and for head officials and game coordinators to ensure that the teams playing have a high luminance contrast between their kits.

Testing for luminance difference can be done by taking a photo of the kit and converting it to greyscale. Remember that some colours (green is especially bad for this) may appear bright to your eyes but are actually quite dark when converted.

Further reading