Primary colours in additive light theory:
Title: Colour theory Date: 20/10/2019 Template: slidy Status: draft Tags: resource
What is colour ?
Light is a electromagnetic radiation, meaning, on it’s own it is invisible, we can use tools to measure it, but to our eyes, light is invisible. We see the effects of light.
Our eyes are full of various receptors that enable us to see colour
Both of these are what we call photoreceptor cells, meaning, sensitive to light.
Rods are most numerous, about 120 million of them per eye, they are more sensitive to light than cones, but not sensitive to colours. They give us the ability to see in low light.
Cones are counted in the 6 million per eye, they are the cells that let us see various colours in the day time. They are sensitive to different wavelengths.
What we see with our cognitive brain is light hitting a surface.
This is what we call additive theory. It can also be called light theory, it deals with radiated and filtered light.
What happens if you mix Red, Green and Blue paint together ?
it is called subtractive theory and can also be called pigment theory because we are dealing with pigments of colour, absorbing certain wavelengths of the light spectrum
Additive colour theory deals with how we see light and is used on screens, in video and photography
Subtractive colour theory deals with how light is reflected off of pages, canvases or card and is used in printing and painting.
We need colour codes to be able to communicate colours between people and software but also between designers and printers
There are two basic colour systems to reflect both the additive and subtractive
but as soon as you plan on printing your documents on screen, you must switch to
RBG = Red, Blue, Green
CMYK = Cyan, Magenta, Yellow, K: for Black
(K is for Key, used instead of B for Black, because in some printing cases, we use a 4th or even 5th colour instead of Black for Key reference)
The property of colors by which they can be perceived as ranging from red through yellow, green, and blue, as determined by the dominant wavelength of the light.
The vividness of a color’s hue. Saturation measures the degree to which a color differs from a gray of the same darkness or lightness.
Attribute of visual sensation according to which an area appears to emit more or less light. Lightness, more or less white in the color composition.