Some format decisions only announce themselves later. A logo that looked sharp on screen turns fuzzy on a three-metre banner. A photograph saved as an SVG refuses to open. Knowing which of the two file families to build in—and when to switch between them—saves a great deal of rework.

Vector and raster are not rivals. They solve different problems, and most projects end up needing both, occasionally inside the same document.

What each format actually is

Raster files—JPEG, PNG, TIFF, PSD, and almost every photograph taken on a phone—are grids of pixels. Each pixel stores a colour value. The image exists at the size it was created, and that is the end of it.

Vector files—SVG, AI, EPS, and most PDFs—store geometry instead. A circle is a centre point and a radius. A curve is a set of coordinates with handles on either side. Nothing is tied to a grid, so the software can redraw the artwork at whatever size the output device allows.

Almost every practical difference follows from that one distinction.

Resolution: the number that shapes your workflow

Resolution applies only to raster images, and it is usually expressed as pixels per inch (ppi) for screen work and dots per inch (dpi) for print. For printed photographs and detailed artwork, 300 ppi at final size is the long-standing benchmark. Large-format pieces such as posters and exhibition panels are often acceptable at 150 ppi because they are viewed from several feet away. On screen, a web image at 1500 pixels wide is generous; much larger and you are shipping bytes nobody will see.

The common mistake is placing a small raster image and scaling it up. A 400-pixel logo stretched across an A4 page will look soft on screen and embarrassing in print. Editing software will stretch it anyway, but it cannot invent detail that was never captured. Vector artwork sidesteps the problem entirely: scale a vector logo from a business card to a building wrap and the file recalculates rather than resamples.

Editing habits: pixels versus paths

Raster editing is about tone and texture. Retouching a portrait, compositing several exposures, grading colour, painting grain into a background—all raster work, because you are changing what individual pixels contain.

Vector editing is about structure. You move anchor points, adjust curves, align objects to a grid, and set stroke weights in millimetres. Type stays editable. You can change one brand colour and watch it update across an entire identity system in seconds, because it is one swatch rather than thousands of pixels.

That is why logos, icons, diagrams, packaging cut lines and signage are built as vectors, while photography and painterly illustration are built as rasters.

Colour, effects and the awkward in-between

Raster files carry colour as pixel data, which suits RGB screen work, CMYK print, gradients and photographic nuance. Vector files carry colour as fills and strokes, which suits flat colour, spot colours and precise print specifications.

The mixed cases cause most of the confusion. Soft shadows, blurs and textures are inherently raster effects. When a vector file needs one, the software either embeds a raster image or converts part of the artwork to pixels on export. That is fine, provided you know it has happened. A PDF containing vector type alongside a flattened drop shadow is still editable, but the shadow will not scale as cleanly as everything around it.

Complex vector files can also grow heavy. A simple icon is a few kilobytes; a detailed map with thousands of paths can rival a photograph. Vector is not automatically lighter, only usually lighter.

Matching format to project

A rough guide for the work that lands on your desk:

• Logos and brand marks: build the master as vector, then export PNG or SVG at whatever sizes you need.
• Photography: shoot and edit as raster. Keep a high-resolution master and export smaller copies for delivery.
• Icons, wayfinding and data graphics: vector, so they stay crisp at every size and remain editable.
• Print collateral: vector type and shapes, with 300 ppi raster images placed inside the layout.
• Large-format banners and vehicle graphics: vector wherever possible, and check any placed image at final size before signing it off.
• Web and app interfaces: SVG for icons and simple graphics, raster formats for photographs.
• Email: keep it simple with PNG or JPEG. Many email clients handle SVG poorly.

Converting between the two without losing sleep

Vector to raster

This direction is straightforward and effectively irreversible, so export last and export generously. Set 300 ppi for print, a sensible pixel width for screen, and leave the vector master untouched. If a client later asks for a bigger version, you go back to the master rather than enlarging the export.

Raster to vector

This direction is harder. Automatic tracing works reasonably well on high-contrast, simple shapes: a scanned signature, a flat single-colour logo, a rubber stamp. It produces hundreds of messy nodes on photographs, gradients and anything with soft edges. If a client sends you a JPEG logo, tracing can be quicker than chasing the original file, but expect to tidy the paths and rebuild any text as live type.

Keep every master file in a folder clearly marked as such, and treat exports as disposable. The master is the version you cannot recreate.

A quick routine before you start

Ask four questions in order. Does this need to hold up across very different sizes? If yes, vector. Is it photographic or heavily textured? If yes, raster. Will it be printed? Then plan for 300 ppi raster elements with vector type and shapes on top. Does somebody else need to edit it in an ordinary office program? Then supply a flattened PNG or JPEG and keep the working file to yourself.

Answer those honestly and the choice usually makes itself. When you are still unsure, build the master in whichever format loses the least information—vector for shapes and type, high-resolution raster for photographs—and export downwards from there. The next request for a larger version, usually due the following morning, becomes a two-minute job rather than a redraw.

Photo: Sonya Kovalski / Pexels