- [Narrator] Now that we know the way
light is stored as a number using bit depth,
we can begin to think about color.
Actually, working with color is only slightly more complex
than working with, a single, monochrome light or dark pixel.
When we speak of color, we are actually
speaking of color channels,
and these are a little like audio channels.
Cameras sometimes capture only the brightness of an image
but they generally capture red green
and blue lights separately.
There are few ways of approaching this
but I want to focus on RGB which is the red,
green, and blue light.
RGB is three numbers that represent the amount
of red, green, or blue a pixel has.
The system that records color information,
Is only a tiny bit more complex
than measuring the light information
using bits as we did in the previous lesson.
The difference is that the information is used
to record different colors.
Each color is described as a channel.
Think of a channel as a single signal
carrying one kind of information.
The red channel contains the amount of red in the pixel,
so a pixel with a 128 red value
would have a 50%
of the total maximum amount of red.
The amount of red that is possible
is a little like the amount of light that's possible,
in that we're not talking about the maximum amount
of red that can exist in a spot in this entire universe,
we're talking about this particular recording system,
and ultimately, someone's TV or cinema projector.
There are standards that define the amount of red
that can be called fully red.
And, most systems adopt one or the other.
sRGB is one, DCI P3 is another.
And these are pretty boring names aren't they?
But they are important because if everyone agrees
on an amount of red that's fully red,
well, then we can use this as a reference
and be confident that what we're capturing, editing,
and displaying will match our expectations,
and everyone else's.
So let's get back to our color channels.
Now, we have a red color channel with eight bits
used to store the amount of red,
we also need a green channel and a blue channel.
Each channel uses eight binary bits of data
to store the amount of color,
atleast that's the case with eight-bit images
or eight-bit color.
This means in reality, when we speak about
eight-bit color, we're truly speaking
about 24-bit color.
That's three times eight.
In all the systems, this was sometimes
the name given to this kind of image.
But it got a little confusing when actual
24-bit color was possible because,
well, what do you call it?
So now most people pretty much refer to
eight-bit color or images or video as eight-bit
even though 24-bits per pixel are actually used.
The colors we usually see on computer screens,
TVs, and cinema screens are created by combining
red, green, and blue pixels that are recorded
and reproduced each on a scale from zero to 255.
And you can see pretty clearly what's happening here.
As we adjust the numbers for these three channels.
Now, there are a few ways for approaching
the distribution of numbers,
different ways of measuring color,
and more or less bits assigned to the process.
But this is pretty much all you need to know
to understand the menus you'll encounter
when working with color pixels in the future.
There are a specific number of colors
that can be created.
That's 16,777,216 possible colors.
That's a lot of colors, in fact it's more
than the human eye can see.