
Why tennis balls are yellow or green - Tomte
https://www.artsy.net/article/artsy-editorial-reason-tennis-balls-yellow-green
======
ninjinxo
Tennis balls are fluorescent; UV light gets reflected back as a set
wavelength. This means they'll be brighter than a non-fluorescent yellow/green
and thus easier to see. The amount of UV light (time of day, natural vs
artificial light, overall light levels) will push the subjective colour
between green and yellow.

This becomes a minor consideration when doing tennis court lighting upgrades,
as Metal Halide lamps emit UV whilst new LED ones don't. Since tracking of the
ball is primarily based on strong and consistent contrast against the
background, having a UV light component that only lights the tennis ball is a
major boon.

Tennis can be played under blacklight with relatively weak lights:
[https://www.youtube.com/watch?v=-x4mfQITXtM](https://www.youtube.com/watch?v=-x4mfQITXtM)

See also: [https://www.stevespanglerscience.com/lab/experiments/uv-
reac...](https://www.stevespanglerscience.com/lab/experiments/uv-reactive-
beads/)

~~~
agumonkey
I wonder how many daily things still have fluorescent elements. In the 90s
there was a little fad (my ikea bed light has a fluorescent switch, and we had
a few items like this).

~~~
analog31
White shirts and office paper have fluorescent dyes.

~~~
wongarsu
This is also how "whiter than white" detergent works.

~~~
kevin_thibedeau
And why bees will sometimes harass people that look too much like a tasty
flower.

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jessriedel
The answer:

> For nearly a century, tennis balls were white or black...In the late 1960s
> ...the BBC... broadcast Wimbledon, perhaps the most iconic of tennis
> tournaments, in color for the first time ever.

> Broadcasting tennis in color brought the matches to life, but it made
> tracking the ball on screen difficult — especially when it fell near the
> white courtlines. So the International Tennis Federation (ITF) undertook a
> study that found that yellow tennis balls were easier for home viewers to
> see on their screens. An official 1972 ITF rule change required that all
> regulation balls have a uniform surface and be white or yellow in color.
> However, despite the difficulties for TV viewers, Wimbledon did not change
> the ball color to yellow until 1986.

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ddek
Far more interesting than the colour is the weight. A lot of tennis critics
these days think the surfaces are becoming more similar - clay is getting
faster, grass is getting slower, etc.

What has actually happened is the various federations change the ball based on
the speed of the surface. Slow courts get faster moving light balls, and vice
versa.

This is actually very well documented the ITF have posted everything from
press releases to research papers - but commentators still seem to think that
the composition of mud has changed significantly in the last 10 years!

~~~
hackandtrip
It's the first time I heard this and I'm really surprised. Do you have any
link related for those press releases?

A simple Google search doesn't seem to give any good results and ITF's site is
not the most user friendly for searching.

~~~
ddek
[https://bleacherreport.com/articles/547256-how-the-humble-
te...](https://bleacherreport.com/articles/547256-how-the-humble-tennis-ball-
has-hepled-change-the-game)

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vonseel
I was an average tennis player in high school and later took a class in
college.

The only scent as powerful and nostalgic as tennis balls that I can think of
is that of a new car. It must be some weird chemicals or adhesives used in the
manufacturing process. I sure do love it, though. I’ve actually got a bottle
of new car smell concentrate which is half decent that I use instead of
candles and typical scents at home. I’d buy a tennis ball scent if they sold
that, ha.

~~~
vagab0nd
What about the smell of new electronics?

~~~
thirdsun
Yes, new Apple hardware in particular has a very distinctive, pleasant and
hard to describe smell.

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gumby
The flouro wasn't adopted immediately. When I was on my high school tennis
team (79-82) we mostly had white tennis balls except when some kid brought in
a tube of the "exotic" ones.

We had wooden rackets (stored in press frames) back then too. The modern game
of tennis is practically unrecognizable when compared to that era.

(Get off my lawn! I suppose).

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nateburke
Wimbledon used to use white slazenger balls.

[https://images.app.goo.gl/W7Edd15tbHbB8Kkq8](https://images.app.goo.gl/W7Edd15tbHbB8Kkq8)

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WilliamEdward
Essentially it's for the exact reason you think: so people could see the ball
better.

The interesting part is that it wasn't for the players to see the ball better,
but television watchers.

~~~
praptak
They tried to do it digitally with the hockey puck (FoxTrax glowing puck tech)
but it got poor reception.

~~~
Jamwinner
If they has set the trails to 20 instead of 100, I think it would have bugged
less people. As it was, it popped too much and made the game look like a
background.

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Doubl
Same reason high visibility jackets are I presume. I always think they're
green but others tell me they're yellow. I have normal color vision as do at
least some of the people who see them differently

~~~
werdnapk
I always just assumed school buses were yellow because they're always referred
to as yellow, but then my 3 year old child said "look at the orange bus" and
as I looked, I realized that indeed the colour of a bus appears to be more
orange than yellow. Now I can't un-see it.

~~~
Doubl
Can't imagine confusing orange with yellow. Do you know what the general
consensus is on the color?

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corobo
Woah this is weird. I just re-listened to the Hello Internet episode where
they were discussing this question.

Ask HN: Am I in The Truman Show?

~~~
ReverseCold
Baader-Meinhof Phenomenon :)

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alanbernstein
This gives me an idea for "hard mode" tennis, with camouflage balls...

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growlist
'Why clickbaity headlines that bait you with the answer to an unasked question
are annoying'

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cxa
The original article on Artsy (which CNN links to) is better illustrated:

[https://www.artsy.net/article/artsy-editorial-reason-
tennis-...](https://www.artsy.net/article/artsy-editorial-reason-tennis-balls-
yellow-green)

~~~
dang
Changed from [https://edition.cnn.com/style/article/artsy-tennis-ball-
desi...](https://edition.cnn.com/style/article/artsy-tennis-ball-design-
artsy/index.html). Thanks!

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foreigner
TL;DR: they used to be black or white but changed to yellow for colour TV.

~~~
lultimouomo
Also, there aren't two different colors of balls, yellow and green. There is
one official color that some people judge as yellow and some as green.

~~~
willismichael
Being a stickler about color theory, I keep trying to get people to say that
tennis balls are chartreuse, but I don't have a lot of luck:
[https://en.wikipedia.org/wiki/Chartreuse_(color)](https://en.wikipedia.org/wiki/Chartreuse_\(color\))

To me, calling that color "yellow or green" is like trying to use the words
"red or yellow" to describe orange.

~~~
chrisseaton
They look more like yellow than chartreuse to me. Colour names are all opinion
- not much point arguing about it or trying to convince anyone of your
opinion.

