Image Size & Colour Depth Flashcards

All 4 cards in this deck

What is colour depth?

The number of bits used to represent each pixel.

What is the image size of a bitmap?

Its width $\times$ height, measured in pixels.

How many different colours can an image with a colour depth of $n$ bits contain?

$2^n$ colours.
e.g. a colour depth of 1 bit allows just 2 colours, such as black and white.

How do you find the minimum colour depth for an image with a given number of colours?
e.g. an image with 5 colours

Find the smallest number of bits $n$ where $2^n$ is at least the number of colours.
e.g. 2 bits give only 4 colours, so 5 colours need 3 bits.