Raster vs Vector: What’s the Difference?
Raster and vector are the two fundamental types of digital image. Understanding the difference is essential for choosing the right format for print, web, and design workflows — and for knowing when DPI matters.
What Is a Raster Image?
A raster image stores visual information as a rectangular grid of pixels, where each pixel holds a specific colour value. The total number of pixels is fixed at the time of creation or capture. Common raster formats include JPEG, PNG, WebP, GIF, TIFF, HEIC, and BMP.
Because raster images are pixel-based, they have a fixed resolution. Enlarging a raster image beyond its native pixel count requires resampling (interpolating new pixels), which reduces sharpness. This is why DPI matters for raster images: the ratio of pixels to inches determines print sharpness. Convert your image to 300 DPI to prepare it for sharp professional print.
What Is a Vector Graphic?
A vector graphic stores images as mathematical descriptions: paths defined by anchor points, curves, fill colours, and stroke properties. When a vector image is rendered — on screen or by a printer — the maths is recalculated at the output resolution. Common vector formats include SVG, AI (Adobe Illustrator), EPS, PDF, and WMF.
Vectors scale infinitely without quality loss: a 2 KB SVG logo renders equally sharp on a business card or a 10-metre billboard. Vectors have no inherent DPI because they have no pixels — DPI only becomes relevant when you export a vector to a raster format.
Raster vs Vector: Key Attributes Compared
| Attribute | Raster | Vector |
|---|---|---|
| Scalability | Fixed; degrades on enlargement | Infinite; no quality loss |
| DPI requirement | Yes; 300 DPI for print | No (set at export) |
| Best for | Photos, complex imagery | Logos, icons, type, diagrams |
| Common formats | JPEG, PNG, WebP, GIF, TIFF | SVG, AI, EPS, PDF |
| File size | Depends on pixel count & compression | Typically small for simple graphics |
| Photo-realism | Yes | Difficult; not suitable for photos |
DPI and Raster Images
Raster images have a DPI tag stored in their metadata (EXIF for JPEG, pHYs chunk for PNG). This tag tells the printer how many pixels to map per inch. For sharp consumer print, set 300 DPI using the DPI Converter. For large-format print, check whether 150–200 DPI is sufficient given the viewing distance. Use the Print Size Calculator to calculate the correct pixel count for any DPI and output size.
DPI and Vector Exports
When you export a vector to a raster format — for example, exporting an Illustrator AI logo to PNG — you specify the output DPI at export time. Exporting at 300 DPI at 3″×3″ produces a 900×900-pixel PNG. Export the same file at 150 DPI and you get a 450×450-pixel PNG. The vector source is unchanged; only the rasterised export reflects the DPI.
When to Use Raster vs Vector
- Use raster for: photographs, screenshots, digital art with complex gradients, web images, social media images.
- Use vector for: logos, icons, brand marks, typography, technical diagrams, anything needing multi-size output (business card to billboard).
- Use both for: multi-layer print documents (PDF) combining a vector logo with a photographic background.
Working with a Raster Image?
Check and set the correct DPI for your print job using our free tools.
FAQ
Does a vector logo need 300 DPI? The original vector does not. If you export it to a raster format for print, export at 300 DPI at the final print size.
Can I convert a photo to vector? Auto-tracing tools create vector paths from raster outlines, but photographs contain too much detail to vectorise faithfully.
Why does my PNG logo look blurry when printed large? A PNG is raster — it has a fixed pixel count. If exported too small, it will look blurry at large print sizes. Request an SVG or AI vector from your designer, or upscale the PNG before printing.