BRUCE

When we open our eyes and look around, does everyone see the world in the same
colours? What is color anyway? Let's find out!

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When you were a small child, I am sure you mixed together lots of different
coloured paints. The more paint that you mixed, the more the color turned into
a thick black goop.

NARRATOR

When you were a little older, I'm sure that you mixed together Red & Green &
Blue light. You were probably surprised to discover that this created a white
patch when all the intensitites were the same.

NARRATOR

You may know that our the light entering our eyes has some wave-like properties.
The wavelength of the light tells us how much energy the light has, but also
tells us what colour it will look like.

NARRATOR

Our eyes can see light from around 400nm that appears violet to a aound 700nm
that appears red. When these wavelengths are mixed in just the right ratios we
see white light. By some crazy coincidence those ratios are that same as the
spectral distibution coming from the sun - who knew the sun was actually white
if it's not rising or setting?

NARRATOR

We've all seen these colors in rainbows and we know that when there is very
little light we see in black and white - that's our night vision.

NARRATOR

Inside our eyes we have 4 sorts of receptor. Cones for Red, Green and Blue as
well as Rods that see in black & white when it's very dark. Curiously color
is something that only really exists inside our brains. When we look at a blue
LED, there are lots of blue photons entering our eye. When we look at blue paint
there are still blue photons entering our eye which means the paint must be
absorbing every other color except blue - kind of like a color sponge.

NARRATOR

If white paint reflects all colors then why isn't a mirror white? A mirror will
reflect all the rays of light back the way they came - it preserves the
brighness and direction and wavelength of all the light.

NARRATOR

White paint actually has a transparent skin allowing light to enter the paint
where it is scattered inside the skin. Some light is reflected back out at
random angles, other light is refracted

(in other words changes color a bit)

before coming back out. All this bouncing around does not preserve the direction
of the light and this light diffusion is one thing that makes it look different
to a mirror.

NARRATOR

Back in the 1920s the French Commission Internationale de l'éclairage (CIE) did
some experiments to try and measure the colors that people could see and they
made an RGB model where three very specific visible reference colors are mixed
to make all the other colors in a printing or cinema process.

NARRATOR

Some humans can experience colors that are redder than the reference Red or
greener than the reference Green. The CIE made another reference color space
called XYZ where Y represents luminance which is like brightness.

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This means that for any value of Y, the XZ components show all the possible
chromaticity values for that luminance. It also means that all the possible
colors that a human can see can always be represented by three positive numbers
X, Y & Z. You might have seen some of these charts in video editing manuals.

NARRATOR

We might have made the maths easy back in the 1930, but the brain is a funny
thing. Look at the Adelson's Checker-Shadow Illusion and tell me which is darker
square A or B? Look closely. Now I'll remove the fake shadow.

NARRATOR

It will come as no surprise that if our brain process imagess to ignore actual
brightess and to interpret everything as relative brightenss, then we are likely
to do the same thing with color. Take a look at the Munker Effect illusion,
thanks to Professor David Novick at the University of Texas at El Paso. What
color are the balls?

NARRATOR

Let's take a closer look with parts of the lines removed. The point is that
part of sseing color is science and part is the composition and art in the
image.

NARRATOR

This is important today becase we are re-inventing Television, streaming and
screens with High Dynamic Range, LED walls and wide color gamut. That means
redder reds, greener greens and blue-er blues than ever before. We need to do
this and still have movies, TV shows and sports look good.

NARRATOR

Today, if you capture all the light possible in the camera and never throw the
originals away, you can make content that looks great today and should still
look great in the future!

BRUCE

Thanks team. Check our the Bruce's Shorts website for links and extra resources.