A bitmap image of a logo is stored in binary.
Describe how the pixels in the logo are represented in binary, and how the number of bits available for each pixel can limit the image.
Mark scheme
Award up to two marks for a linked description such as:
- Each pixel is a single colour (1) that is stored/given as a binary value (1)
- Each pixel is represented by a binary value (1) which gives/represents its colour (1)
- The pixels are stored in order/rows (1) so the binary values can be read back to recreate the image (1)
- Each pixel uses a fixed number of bits/colour depth (1) so only a limited number of colours can be represented (1)
- The number of bits available for each pixel is fixed (1) so some colours cannot be stored/shown (1)
Allow '1s and 0s' for binary value.
For the first mark, accept a statement that a pixel is stored/represented by a binary value; do not award the first mark for 'grid of pixels' or 'a pixel is a single colour' alone unless it is linked to a binary value.
Do not accept 'a pixel is a small dot' alone.
Do not accept responses that only describe file size or resolution.
Example answers and how they were marked
Each pixel is a single colour and its colour is stored as a binary value. The number of bits for each pixel is fixed, so only a limited number of colours can be represented.
Why: Linked point (1) that each pixel is a single colour and development (1) that its colour is stored as a binary value; the colour-depth limitation is also creditworthy but the answer is capped at 2.
Each pixel is stored as a binary value.
Why: Point (1) that each pixel is stored as a binary value, but no linked development about the colour it represents.
A bitmap image is made of lots of dots called pixels.
Why: No credit: 'a pixel is a small dot' alone is not accepted because it does not link a pixel to a binary value.