Quick questions on Digital design tools: O-Level Design Studies

Raster, or bitmap, images are made of a grid of tiny coloured squares called pixels. They are excellent for photographs and detailed, continuous-tone images, because each pixel can be a different colour. Their key limitation is resolution dependence: an image has a fixed number of pixels, so enlarging it beyond its resolution makes it look blurry or blocky (pixelated). Raster images also tend to have larger file sizes as detail and dimensions increase.

Vector graphics are made of mathematical paths: points, lines and curves defined by equations. Because they are calculated rather than stored as pixels, they can be scaled to any size, from a tiny icon to a giant banner, with no loss of quality. They produce clean, sharp edges and small file sizes, and are ideal for logos, icons, type and illustrations with flat colour. Their limitation is that they cannot reproduce the fine, continuous detail of a photograph.

Designers use several kinds of tool. Raster (image) editors handle photographs and pixel-based artwork. Vector (illustration) editors create logos, icons and scalable graphics. Page-layout software arranges text and images for multi-page documents such as magazines and brochures.

The right format depends on the use. Common raster formats include JPEG (good compression for photos, but lossy), PNG (supports transparency, good for web graphics), and TIFF (high quality for print). Common vector formats include SVG (scalable graphics for the web) and PDF (reliable for sharing and printing layouts). Choosing the correct format preserves quality, controls file size, and ensures the file works for its destination, whether screen or press.