
How many colours were there in a medieval rainbow? - prismatic
https://forthewynnblog.wordpress.com/2017/11/20/how-many-colours-were-there-in-a-medieval-rainbow/
======
ubernostrum
This is your reminder, should you want to go off the deep end into Sapir-Whorf
linguistic relativism, that peoples whose languages did not have words to
_linguistically_ distinguish certain colors (such as blue and green)
nonetheless demonstrably produced works (such as textiles) with patterns which
required the ability to _visually_ distinguish those colors, and that the
strongest evidence we know of suggests merely that having a word for a color
helps you to recognize it more quickly than if you don't have a word for it,
rather than toggling whether you are capable of perceiving it.

~~~
tudorw
Thanks, that's for me, your position ties with what I've read about cognition
recently, that when we use a new word, it's like a shortcut for the brain, the
more we use a word, the more the shortcut is reinforced. There was also that
bit about Homer describing the sea as the same colour as wine, here's a good
tear down of that
[http://www.abc.net.au/radionational/programs/bodysphere/feat...](http://www.abc.net.au/radionational/programs/bodysphere/features/5267698)

------
Aardwolf
I find our own modern ROYGBIV odd, with R=red O=orange Y=yellow G=green B=blue
I=indigo V=violet

More sense would make: ROYGCBV with C=cyan (or replace the V with P from
purple)

The "indigo" and "violet" are so similar to each other (and even a physically
narrower band in the rainbow), while something is missing between the green
and blue.

I know that it's an analog transition of colors so there are infinite shades
and using 7 discrete names does not match reality, but when we do use names
they should at least match popular language usage and uniform distance better
imho.

Maybe it's subjective?

~~~
yoz-y
There are studies that has show that people can distinguish a color faster and
better if their language has a word for it. If we assume this is true, your
version would work better for english in particular. I suppose that more
people can make a difference between green and cyan and blue and cyan, rather
than between blue and indigo and violet and indigo.

Personally, I do not actually know what indigo is supposed to look like and an
image search shows everything from blue to violet.

~~~
rainbowmverse
The Gamecube is indigo.

~~~
ZoeZoeBee
Nintendo may have called the purple version of the Gamecube Indigo, but Indigo
is a dark blue dye derived from a plant, unless you think your blue jeans
match your GameCube

~~~
rainbowmverse
They're just names for arbitrary divisions of the spectrum of vibrating matter
around us. The HN top bar is still orange even if it's not the same color as
the fruit. My GameCube is close enough to the color of the dye that I'll allow
it. It's also a _long_ way from purple.

~~~
ZoeZoeBee
I'm sorry but the "Indigo" GameCube is much closer to a strict definition of
purple than it is darker blue
[https://en.wikipedia.org/wiki/GameCube](https://en.wikipedia.org/wiki/GameCube)
[https://en.wikipedia.org/wiki/Purple](https://en.wikipedia.org/wiki/Purple)

~~~
rainbowmverse
I'm talking about my actual GameCube sitting in my game storage drawer, which
I checked before making that comment. That image is much brighter and much
more purple than the real thing I had in my hands.

------
bryanlarsen
My kids will tell you there are six colors in the rainbow, that's what they
were taught in kindergarten. The three additive primary colors and their
secondaries. (Although they'll give you the name)

Makes more sense than choosing the number for biblical reasons I guess.
Secondary colors are dual frequency colors, but the rainbow is made solely of
single frequency colors, so that's wrong too. And purple/violet is just weird,
the eye thinks the bluest blue has some low frequency red in it due to its
response curves.

~~~
combatentropy
> Makes more sense than choosing the number for biblical reasons

The Bible doesn't say there are seven colors in the rainbow. Isaac Newton said
so, to match the seven notes of a musical scale.

I agree with your kids. There are six: red, orange, yellow, green, blue, and
purple. In grade school, I heard indigo and thought, who says indigo? You
might as well add chartreuse.

~~~
jandrese
You aren't alone in this sentiment:

[https://blog.xkcd.com/2010/05/03/color-survey-
results/](https://blog.xkcd.com/2010/05/03/color-survey-results/)

First, a few basic discoveries:

Indigo was totally just added to the rainbow so it would have 7 colors and
make that “ROY G. BIV” acronym work, just like you always suspected. It should
really be ROY GBP, with maybe a C or T thrown in there between G and B
depending on how the spectrum was converted to RGB.

------
limbicsystem
Hannah Smithson at Oxford has a beautiful research programme looking at
medieval descriptions of rainbows and their relation to modern color spaces:
here's an example that combines scholarly study of illuminated manuscripts and
data from the Hubble Space Telescope.
[https://www.psy.ox.ac.uk/publications/464345](https://www.psy.ox.ac.uk/publications/464345)

Interesting additional fact: 'rainbows' are not the same thing as the pure
spectra that you might get from a prism.

------
baldfat
To me and my Theology/Philosophy Education I would say that this is a
difference between Aristotle and Plato. Up to the 16th Century the king of
everything Science in Europe was Aristotle and their was always tension
between the two philosopher's theories.
[https://www.diffen.com/difference/Aristotle_vs_Plato](https://www.diffen.com/difference/Aristotle_vs_Plato)

People's worldview were more important than simple observation and is the
biggest difference between modern science and the past, arguably. Isaac Newton
even decided the 7 colors due to his own theory of the world. "Music and the
Making of Modern Science. “It has no justification in experiment exactly; it
just represents something that he’s imposing upon the color spectrum by
analogy with music.” [https://www.the-
scientist.com/?articles.view/articleNo/48584...](https://www.the-
scientist.com/?articles.view/articleNo/48584/title/Newton-s-Color-Theory--ca--
1665/)

Whenever I read articles like this I think it is Aristotle's forms and it is
100% why there are four colors.

From the article

> The reason why the author saw four colours in the rainbow comes from the
> theory of the four elements, an idea which goes back to Aristotle. But why
> those particular colours?

The answer to me is obvious. The "scientifically" held fact was the rainbow
had four colors, because the rainbow represented the four elements. Now
however you wanted to divide up the four colors was the scientific aspect of
thought back than.

I find that the Plato vs Aristotle is not common knowledge in our modern times
and causes a lot of people to view the people of history as idiots because we
look at the rainbow and of course there are more than 4 colors. But they added
"black" or "white" to add their 4th.

------
labster
> going off of unique frequencies, there are more colors in a rainbow than
> there are stars in the Universe or atoms in your body,

Anyone better versed in optics than me care to write this in scientific
notation? I know energy is quantatized and the visible spectrum is bounded, so
there has to be a total amount of wavelengths, right?

~~~
OscarCunningham
>I know energy is quantatized and the visible spectrum is bounded, so there
has to be a total amount of wavelengths, right?

It's only particles in bound systems that are quantized. For examples
electrons in an atom can only have particular energies. But a photon from a
rainbow is just flying through free space, so I think it can have any
frequency.

------
etqwzutewzu
"Isidore’s encyclopaedic work De natura rerum asserts that there are"

\- but "De natura rerum" is Lucretius's poem

\- Isidore of Seville's encyclopedia is "Etymologiae"

\- "De rerum naturis" (De Universo) is Rabanus Maurus's encyclopedia

what is the correct one?

~~~
etqwzutewzu
(answering to myself) "De natura rerum" seems to be also the name of a part of
Etymologiae (TBC)

------
NelsonMinar
There are 6 colors in the typical computer HSV rainbow.
[https://visual.ly/blog/wp-
content/uploads/2012/04/RainbowEdg...](https://visual.ly/blog/wp-
content/uploads/2012/04/RainbowEdges.png)

At least that's what I see if you uniformly vary hue and display it in the
usual sRGB display. (7 bands, red is repeated). That's why naive rainbow
visualizations are such a bad idea and visualizations should use perceptual
color scales instead. For

Caveat: these perceptions are culturally relative. I'm born and raised in the
US.

~~~
OscarCunningham
People were mad when Pluto got demoted. Can you imagine the riots if orange
lost its status?

------
corprew
A great book that discusses this and a lot of other cognitive categories is
George Lakoff's _Women, Fire, and Dangerous Things_.

Highly recommended for everyone that makes things that use categories, tags,
criteria, &c.:
[https://en.wikipedia.org/wiki/Women,_Fire,_and_Dangerous_Thi...](https://en.wikipedia.org/wiki/Women,_Fire,_and_Dangerous_Things)

------
tragomaskhalos
Colour perception is indeed fascinating. My son is autistic, and his
attachment of labels to colours is idiosyncratic - e.g. one of his favourite
things is an Angry Birds pig plush, which he insists is "yellow". This makes
complete sense to me once we mentally translate to a different classification
scheme - I believe he is seeing the (classical) Greek "khloros", the vibrant
colour of growing vegetation, for which we don't have a precise word in
English.

~~~
solipsism
What? That kind of green is clearly a yellowish green, like the Greek nymph.
But what does that have to do with "different clarification schemes"? You seem
to be implying that your son's scheme is aligned with that of the ancient
Greeks, but I'm not seeing it. Could you elaborate?

------
SetTheorist
An in-depth analysis of basic color terms across languages:

[https://www.amazon.com/Basic-Color-Terms-Universality-
Evolut...](https://www.amazon.com/Basic-Color-Terms-Universality-
Evolution/dp/1575861623/)

(Noting that different languages do have differing numbers of basic color
terms.)

------
Camillo
[https://en.wikipedia.org/wiki/Color_term#Basic_color_terms](https://en.wikipedia.org/wiki/Color_term#Basic_color_terms)

------
theaeolist
Is there any colour (by hue) not in the rainbow?

~~~
limbicsystem
I don't know about 'by hue' but almost all colors are not in the rainbow. The
spectral locus is a line that runs around the edge of a 2D color space
(technically 3D if you include luminance as well...).

7D if you are a mantis shrimp.

~~~
rlonstein
> 7D if you are a mantis shrimp.

Don't be sure:

* [https://www.popsci.com/blog-network/ladybits/mantis-shrimp-v...](https://www.popsci.com/blog-network/ladybits/mantis-shrimp-vision-not-mindblowing-you%E2%80%99ve-been-told)

* [https://phys.org/news/2014-01-mantis-shrimp-vision-different...](https://phys.org/news/2014-01-mantis-shrimp-vision-differently-video.html)

Though they do see polarization, which is a neat feature.

------
warent
"The four created things in which all earthly things exist are aer, ignis,
terra and aqua. Aer is air, ignis is fire, terra is earth, and aqua is water."

They actually weren't too far off. Sure, we have many more elements than just
four, but there are only four states of matter. Although of course fire isn't
literally plasma, but in a sense, they had essentially grasped this truth
about these four fundamental states

~~~
ramchip
There are more than four states of matter, but it’s true only the classical
four would have been observable to a medieval person, so that is an
interesting parallel.

~~~
thaumasiotes
There are no four classical states of matter. Nor, relatedly, would plasma
have been observable to a medieval person. What parallel?

~~~
benbreen
People could see lightning (which so far as I know, is a form of plasma) in
the Middle Ages and relate it to the element of fire, no?

~~~
thaumasiotes
That is possible. However, the plasma state of matter cannot actually be
observed (by a medieval person, etc.). How would they have determined that
lightning, which is visible as a glowing plasma, does represent a state of
matter different from solid / liquid / gas, but fire, which is visible as
glowing, does not?

If you're willing to grant that they can't, then in what sense is it possible
for them to observe plasma?

~~~
ggggtez
Don't be pedantic. So what if fire isn't plasma. They categorized the world by
states of matter, but in a way which is not exactly parallel to modern people.
Acknowledging that there world is made of mixture of fundamental elements was
a great scientific achievement, even if it was wrong about how it worked.

~~~
benchaney
GP isn't being pedantic, although I believe there was a significant
misunderstanding. I think that ramchip meant fire, earth, air, and water, when
he said "four classical states of matter, where as GP thought he meant solid,
liquid, gas, and plasma.

~~~
thaumasiotes
>> So what if fire isn't plasma. They categorized the world by states of
matter

> I think that ramchip meant fire, earth, air, and water, when he said "four
> classical states of matter"

That was the best interpretation I could come up with too. I wasn't saying
fire isn't plasma, though of course it isn't. I was saying fire is not a state
of matter. "They categorized the world by states of matter" is not correct.

For example, the ancients were well aware that ice was a form of water, not a
form of earth.

~~~
bryanrasmussen
since fire is not a state of matter, they were incorrect in what they admitted
to their category of the various states of matter, but they still categorized
fire as a state of matter and as such categorized the world by states of
matter.

The interesting part was supposed to be that they came, with their categories
relatively close to the actual classical categories - however I suppose that
the classical categories were actually intellectually derived from (or their
conception inspired by) the ancient 'elements'.

~~~
thaumasiotes
> they were incorrect in what they admitted to their category of the various
> states of matter, but they still categorized fire as a state of matter and
> as such categorized the world by states of matter.

No they didn't. Why do you say so?

