The colour pink exists only in your imagination.
Every colour in the rainbow has a wavelength light
in the visible spectrum, but there's no pink in a rainbow.
Your eyes contain three types of cone cell -
red, green, and blue.
which are most sensitive those wavelengths of light
As your cone cells are stimulated they send a signal to your brain
which creates image based on that information.
For example, when yellow light enters your eye
both the red and green cone cells are stimulated,
because yellow is between red and green on the spectrum
Your brain receives that information and recognises it as yellow.
When you mix red and blue light, the colour in between them is green –
but your green cone cell isn’t detecting any light of a ‘green’ wavelength.
So, if you're red and blue cone cells are being stimulated
but there's no green light, your brain invents a new, imaginary colour: pink.
This optical phenomenon is also how the pixels of a screen create the colours that you see.
Instead of having to have a different pixel for every single colour,
each tiny pixel is split into red, green and blue subpixels
You can see this for yourself by hacking a macro-lens onto the front of your camera-phone.
So, if we hold it up to this screen – we can see the subpixels.
As the proportions of red, green and blue change, our brains perceive different colours.
A full-HD display of nineteen-twenty (1920) by ten-eighty (1080)
has a total of two-million, seventy-three thousand, six-hundred (2,073,600) pixels.
It’s the combination of these millions of tiny pixels, all working in unison, which creates the image that we see.
And this is happening right now as you watch this video...
There’s no yellow, or cyan, or magenta light leaving your screen;
it’s millions of combinations of red, green and blue
stimulating your cone cells and tricking your brain.
The number of pixels on a screen is known as its ‘resolution’.
You can change the resolution of this video by clicking the gear in the bottom right corner.
Notice the difference in quality between 144p and 1080p
A greater density of pixels gives you a sharper image.
There’s been a lot of hype about the next generation of resolution – 4K.
4096 by 2160 gives you a whopping...
8,847,360 pixels.
That is four times as many pixels as in high-definition.
We have just opened the UK’s first digital 3D, 4K Planetarium –
and we use not one, but two 4K projectors to recreate the universe inside our dome.
And the way that each of these projectors works is fascinating.
Each one contains a series of six lamps –
the light from these is split by a prism into red, green and blue.
Each of the beams of red, green and blue light
hits a ‘digital micromirror device’, or 'DMD' chip.
Each chip measures only 1.38 inches across,
but each one has 8.8 million microscopic mirrors on its surface –
that's one for every single pixel.
Each one of the micromirrors is just one-fifth of the width of a human hair.
And these mirrors tilt on or off to give you light or dark pixels.
And they tilt 5,000 times every second –
the proportion of on to off determines how bright the pixel is for that second.
After the light is reflected from the micromirror,
it is then recombined with the light from the two other chips
through a lens and projected onto the screen as a single pixel,
and then back into your eye.
So two projectors with over 53-million microscopic mirrors,
moving 5,000 times a second
creates an image of over 13 million pixels in our dome.
At a rate of 120 frames per second
(that’s 60 frames for each eye with our active 3D technology);
our Planetarium produces 1.6 billion pixels every second.
Wow!
Phew!
If you enjoyed this video, hit the like button, share it around
and click on this arrangement of astronaut-pixels to subscribe.
Check out how to make a 3D gif in this video.
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Thanks for watching!
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