Graphics, Image Editing and Digital Animation
What the exam tests
Raster versus vector graphics, resolution and colour depth, file formats and compression, layer-based editing, and digital animation methods. Numerical questions on image size and frame rate are common.
Core rules
- Raster images store a grid of pixels; enlargement reveals pixels. Vector images store mathematical paths and scale cleanly.
- PPI describes pixel density for display/print; DPI is a printer dot measure. Changing print size without resampling keeps pixel dimensions.
- Bit depth: 1-bit = 2 colours, 8-bit = 256 levels per channel, 24-bit RGB = about 16.7 million colours.
- JPEG is lossy; PNG and GIF are lossless. GIF supports 256 colours and simple animation; PNG supports transparency; SVG is vector.
- Animation: frame-by-frame, motion tween, shape tween, and path animation. FPS sets playback smoothness.
Worked example
An uncompressed 800 × 600 RGB image at 24-bit: 800 × 600 = 480,000 pixels; 24 bits = 3 bytes per pixel; 480,000 × 3 = 1,440,000 bytes ≈ 1.37 MB using 1 MB = 1,048,576 bytes. If saved as JPEG, the file is smaller because lossy compression discards detail; pixel dimensions do not change.
Traps
Do not say JPEG is lossless. Do not multiply by 24 and call the answer bytes - divide by 8. Do not claim vector images lose quality when scaled. GIF cannot store full-colour photographs well. Resampling changes pixel count; resizing the print dimensions alone does not.