Why is Light White? Day-to-Day Science
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- Опубликовано: 1 мар 2019
- Why is light white? You may have mixed lots of paints together before to get a brown paint mixture, and we know that light is made up of a spectrum of colours, so why should adding all of these colours together give white light and not brown light?
Sources:
en.wikipedia.org/wiki/Cone_cell
So, why is light white? To start off with, we need to consider another question: how does colour work?
Why is light white? It's not an obvious problem at first, but if we mix red, blue, and green paint together we get brown, but if we mix red, blue, and green light together, we get…. white. Why does this happen, and what's going on? Keep on watching to find out more.
It's common knowledge now that white light is actually made up of a spectrum of colours, and this is a fact that I've never questioned before, until I thought about adding all of the colours in the spectrum together. If we did this with paint, we get a brown colour which bears no resemblance to the pure, white colour which we are told light forms.
The issue is that adding paint together and adding light together are two very different things. When you mix paint, the colours are subtractively mixed, whereas light undergoes additive mixing. What do these terms mean though?
First off, we need to look at what’s happening when we perceive colour. If we look at a red car, what is actually happening is that white light from the sun is reflected from the body of the car to meet with our eyes. However, the reason for the red colour is that not all of the light is reflected. Remember that white light is actually made up of a spectrum of colours, and certain materials will absorb different colours better, leaving a reduced spectrum which is reflected. In the case of our car, only the reddish colours are not absorbed, hence giving a red colour which is reflected to reach our eyes. If we mix two colours of paint, yellow and blue for example, both paints will absorb different colours of light, which gives them their distinct hues, but since there is no overlap of these, we don’t see a yellow mixture or a blue mixture. Instead, we get a colour where there is overlap of the reflection colours of these two paints, giving the familiar green appearance of our mixture.
This is known as subtractive mixing, and is very different from the way in which light is mixed. Imagine we start with no light, giving no colours in the spectrum. Now we add violet and blue light, which gives a blue colour to the spectrum, and since the mixing is additive, there is no need for overlap to give the colour; all of the colours are present in the resulting mixture. If we keep adding all these different colours, we can build up an entire spectrum to give white light.
However, you may know that we can create white light from just red, green, and blue light, so how does this work if not all of the spectrum is filled? The answer to this is given by the composition of your eye, and how we see colour in the first place. In the retina, there are cells known as cone cells lining the surface. There are three different types of cone cell; one which can detect blue light, one which can detect green light, and the last which can detect red light. When green light is shone into your eye, the green cone cell detects this and sends a message to your brain to say that green light is being detected. If all three of red, green, and blue lights are detected by the cone cells, they all send messages to the brain, which interprets this as white light. So now you know why adding lots of paint colours together gives a brown sludge due to the limited overlap of all these paints, and why tv screens only need red, green, and blue LEDs in them to produce any colour.
I’ve watched a video about butterflies having their blue color as not a pigment but a reflective aspect created by their wings’s to create the blueish hue. Does that have the same principle to this video?
My paint only gotten wasted because I've tried to make white using these ideas of you
When I mix red, blue and green colour 🔴+🔵+💚= dark green🌲🍀🌿.
Depends on how much color you use(like, more green, less blue)
No, is ✨dark blue✨
You used a specific shade of those colors.
When you mix red, blue and green what? paints, lights, pencils, filters, fabrics ?
It's light bro 😂
Accurate!
great video. thanks
Thanks dude...now I understand
I agree dude
Me too
Thank your explanation is too good
I have a white light in my room! So I have red green and blue together to make it
thanks for explain
It doesn't work
This video should have over 5k likes and views easily.
I'm surprised by this thank you
I try but it comes dark green
yes🤬
It worked out.....😎😎😎 Thank you 😊😊😊
❤
Is not working for me
Yeah science is real but ever changing, filled with hypothesis/theories and so on it’s always changing never stays the same… in the future they may detect that it’s b.s idk who know science can’t explain everything
👍🏻
The human eye is much more complex, you have to check newest research, how complex human vision is, it is not just RGB behind it. We have also many modes, e.g. during night we perceive differently shapes, colors than during day (scotopic vs photopic vison), etc. My question is: can we see white light or colors in the dark conditions? And there is missing topic about melanopsin.
There is also missing easy explanation of perception of metal look, or gloss, semi-gloss, matt color, and different white colors etc. And what about mirror, how we detect we look in mirror/mirroring surface.
Pure white colour
Why is like a 3rd of the comments pretending like he said you can mix paint to make white, he legit said the exact opposite😅
Very well explained. I don't know what some people here are criticising about. Perhaps they don't have basic science knowledge and are getting confused between light and how we perceive the colour of objects.
Its true
Sunlight from Wet Weathers Made
☀️ + 🌧️ = 🌈
Nice information
You. Are. Aachi
I mix red blue and green but gives me dark green
I mixed red green blue but not possible white colour
Yes you are right i also try it doesn't came white colour it came's dark green
@@antarjyamimallickmallick2229 do not try it with paint. But with light
@@NHJ03 in paint 🎨
I have green to gone white
I tried guys but not white its purple colour😆
Please tell me you tried with light and not paint
Why did I not do it? Why?
Immediately clicked pause when I saw that your source/reference is wikipedia lol you cannot use it as your source.
Hi
No
😢
You are l liar I mixtures this colour and they make dark blue
U
T
Slince of 9 - 11 year old who tries this
It doesn't happen
What doesn't happened?
Fake
That is not true this video is not true
It is the wrong message
That is wrong
What is wrong
Fake 🤥
Faltu
STOP!!LIE IT IS NOT TRU
Only works for light. If you use paint, it wont work
Fake 👎
This is a lie
Fake video
You are fake news 😅
When I mixed,🔴🟢🔵= dark green
For god sake, this only works for light.
Fake
Fake
Fake
Fake
Fake
Wdym fake?