Each pixel in a bitmap image is stored using a number of bits.
Define the term colour depth.
Mark scheme
Award one mark for any of the following:
- The number of bits per pixel (1)
- The number of bits used to represent/store the colour of each pixel (1)
Allow bit depth
Do not accept the number of colours a pixel can have on its own
Do not accept the number of pixels in the image (this is the resolution/image size)
Example answers and how they were marked
Full marks1/1
The number of bits used to store the colour of one pixel.
Why: Gives the number of bits per pixel (1)
No marks0/1
The number of colours that each pixel can use.
Why: Gives the number of colours, not the number of bits; the mark scheme does not accept this on its own
No marks0/1
The number of pixels in the image.
Why: Confuses colour depth with resolution/image size, which the mark scheme does not accept