9618 · 1.2.1
Multimedia - Graphics
Digital images are created in two main ways: as a grid of coloured dots (bitmap) or as a set of mathematical instructions (vector). Understanding this difference is key to knowing why some images get blurry when enlarged and others don't.
Need to know
What you need to know
- **Pixel:** The smallest unit of a bitmap image. Think of it as a single dot of colour.
- **Resolution:** The total number of pixels, usually expressed as width × height (e.g., 1920 × 1080). Higher resolution means more detail.
- **Colour Depth:** The number of bits used to store the colour of each pixel. More bits mean more possible colours, leading to a more realistic image but a larger file size.
- **Common Colour Depths:** 1-bit (monochrome), 8-bit (256 colours), 16-bit (65,536 colours), and 24-bit 'True Colour' (approx. 16.7 million colours).
Explanation
Pixels vs. Paths
- A bitmap image is a grid of tiny squares called pixels.
- Each pixel is assigned a specific colour, determined by the image's colour depth (number of bits per pixel).
- The image file size is calculated by multiplying the number of pixels (width x height) by the colour depth.
- Vector graphics, in contrast, store images as mathematical equations for shapes, lines, and curves, not pixels.