Year 7 · Summer 2 · Raid: Code for a Cause

Designing for an audience: layout, colour and typography

What this lesson covers

Topic 5 Representing images

KS3 Computing · A picture is a grid of tiny squares called pixels. Each pixel's colour is stored as a binary number. More pixels and more colours make a better picture, and a bigger file.

Networks and Digital CommunicationCambridge Lower Secondary Computing 0860

You will learn to

Identify who a poster is for and what its one message is.
Explain how layout, colour and font choices help or hurt a design.
Compare three posters and explain which one works best for its audience.

Success criteria

I can name the audience and the message of a poster.
I can spot a poster with too many colours or text too small to read.
I can use the rules: one message, two colours, text big enough to read from the back.

Key words

Say each word, then read what it means. Every one is in the glossary too.

colour depth: Bits per pixel. Sets how many colours are possible.
Pixel: The smallest single-colour dot of an image.
Bitmap: An image stored as a grid of pixels.
Resolution: Number of pixels: width × height.
Metadata: Data about data, like an image's width and height.
Vector: An image stored as shapes and instructions.

The explanation

Read it here, or open the study page below to go one step at a time with things to try.

More colours = more bits per pixel

Bits per pixel = colour depth. Same rule as before: n bits give 2ⁿ colours.

Colour depth	Colours	Use
1 bit	2	Black and white
2 bits	4	Very early games
8 bits	256	GIFs, retro graphics
24 bits	about 16.7 million	Normal photos

How 24-bit colour works (RGB)

Screens mix three lights: Red, Green, Blue. Each gets 1 byte (0–255). 3 × 8 = 24 bits.

Colour	Red	Green	Blue	Hex
Black	0	0	0	#000000
White	255	255	255	#FFFFFF
Red	255	0	0	#FF0000
Yellow	255	255	0	#FFFF00
Orange	255	128	0	#FF8000

?Why?

Why is red + green = yellow? Mixing light adds colours. Mixing paint takes them away. Screens make light.

Study it

Open the study page and go one step at a time.

Topic 19 · Year 7

Digital life, law and ethics

Using technology well means staying safe, knowing the laws about computers and data, and asking who technology helps and who it harms.

Check yourself

One question at a time. The reason shows after each answer.

Saved on this device.