Screens vs Paper

See how adding three different colours to the computer screen makes the colour white.

But adding similar colours to the paper makes the colour black.

What you just saw was the difference between an additive and subtractive colour model.

Additive models 'add' together colours when they overlap to make a brighter colour. While colours get darker when overlapped in subtractive models.

Drag the diagrams into the right type of colour model:

Well done! An example of an additive model is the RGB colour model, used by almost every screen in the world.

Additive models are great for computer screens as we need to change a black screen into a bright colourful image. Computer screens do this by mixing the colours Red, Green and Blue. This is the RGB colour model!

By blending different amounts of these three colours you can make 16,777,216 unique colours!

Have a play with the RGB sliders below:

There are two other major colour models called CMYK and Pantone. All three models turn colours into values, but the models are used for very different things and work in different ways.

RGB is used for electronic screens
CMYK is used in printing
Pantone is used for fabrics

Well done! You've now seen three colour models and what they're used for.

All of these devices are trying to reproduce the exact colour we see, this is tricky as two people might see the same colour differently!
For example, two people might see a shade of 'green' in a different way.

To get as close to our eye's perception of a colour, different devices use different models for creating that colour.

The models are different as they add up separate amounts of different colours.
Let's look in more depth at RGB and CMYK.

In RGB, every colour has a Red value, a Green value and a Blue value - each ranging from 0 to 255.

In CMYK every colour has a Cyan, Magenta, Yellow and Key (black) value - each ranging from 0-100.

Don't use the wrong model! These devices are trying as hard as they can with their specific models and specific mediums to reproduce the exact colour we see.

With RGB models having nearly 17 million different colours (combinations of red, green and blue) and CMYK having 100 million different colours - these models create a lot of different colours!

But are there even more colours in the world?