Raster vs. Vector: The Fundamental Difference Between Photos and Logos
Raster Images
Made of pixels - Fixed resolution, loses quality when enlarged
Vector Images
Made of math - Infinitely scalable, perfect edges at any size
If you've ever wondered why your logo becomes blurry when enlarged, or why photographs can't be made infinitely large without losing quality, you're dealing with the fundamental difference between raster and vector graphics. This distinction is one of the most important concepts in digital design, photography, and web development.
Core Concept:
- Raster = Photos - Made of pixels, resolution-dependent
- Vector = Logos/Graphics - Made of math, infinitely scalable
- Each has specific use cases and limitations
- Choosing wrong leads to blurry images or huge files
- Most projects need both types at different stages
What Are Raster Images?
The Pixel-Based World
Think: Digital Photography, Paintings, Scans
Made of Pixels
Raster images are composed of a grid of tiny colored squares called pixels (picture elements). Each pixel has a specific color value, and together they form the complete image.
Resolution Dependent
The quality is determined by resolution (pixels per inch - PPI or dots per inch - DPI). Common resolutions: 72 PPI (web), 300 PPI (print).
Enlargement Limits
When enlarged beyond original dimensions, pixels become visible, causing pixelation or blurriness. This is why you can't make a small web photo into a billboard.
Real-World Example:
Your smartphone camera takes raster images. A 12MP camera creates images with approximately 12 million pixels (4000×3000 pixels). If you try to print this at poster size (24×36 inches), you get only about 111 PPI, which may appear pixelated up close.
What Are Vector Images?
The Mathematical World
Think: Logos, Icons, Typography, Illustrations
Made of Math
Vector graphics are defined by mathematical equations - points, lines, curves, and shapes. The computer recalculates these equations for any size.
Infinitely Scalable
Can be scaled to any size without loss of quality. A vector logo looks perfect on a business card and equally perfect on a billboard.
Editable Elements
Each element (shape, line, curve) remains individually editable. You can change colors, sizes, and shapes without affecting the rest of the image.
Real-World Example:
The Adobe logo is created as a vector file. The same file that prints on a tiny sticker (1×1 inch) can be used for a building sign (10×10 feet) without any quality loss. The file contains mathematical instructions like "draw a red square starting at point (0,0) with width 100 and height 100."
Head-to-Head Comparison
| Characteristic | Raster Images | Vector Images |
|---|---|---|
| Composition | Pixels (grid of colored squares) | Mathematical equations (points, lines, curves) |
| Scalability | Limited - loses quality when enlarged | Infinite - perfect at any size |
| File Size | Depends on resolution (can be very large) | Generally small (complex art can be larger) |
| Best For | Photographs, realistic artwork, complex scenes | Logos, icons, typography, illustrations, diagrams |
| Common Formats | JPEG, PNG, GIF, TIFF, WebP, BMP | SVG, AI, EPS, PDF, CDR, DXF |
| Editing Flexibility | Pixel-based editing (Photoshop, GIMP) | Object-based editing (Illustrator, Inkscape) |
| Print vs Web | Both (need correct resolution for each) | Both (resolution independent) |
| Complexity | Better for complex color gradients, textures | Better for clean lines, solid colors, precision |
The Scalability Difference: Visual Demonstration
Scenario: Enlarging 200%
What happens when you double the size of each image type?
Raster (Pixel-Based)
The computer has to guess what colors to add between existing pixels (interpolation). This creates blurriness and artifacts.
Vector (Math-Based)
The computer simply recalculates the equations with new values. No quality loss, just recalculated math.
Understanding Resolution
Screen resolution. Looks good on monitors but pixelates when printed large.
For banners and posters viewed from distance. Acceptable quality.
High-quality printing (magazines, brochures). Crisp detail up close.
Resolution independent. Perfect at any size, any viewing distance.
When to Use Each: Practical Guide
Use Raster For:
Photographs
Digital photos, scanned images, any realistic imagery with complex colors and gradients.
Digital Painting
Artwork created with brushes, textures, and natural media effects.
Web Graphics
Complex graphics with shadows, glows, and photo-realistic effects.
Photo Editing
Retouching, color correction, compositing multiple images together.
Use Vector For:
Logos & Branding
Must work at all sizes - from favicon (16×16) to billboard (10×30 feet).
Icons & UI Elements
App icons, interface buttons, navigation elements that scale for different devices.
Typography & Lettering
Text that needs to remain crisp at any size or resolution.
Technical Drawings
Architectural plans, engineering diagrams, maps with precise measurements.
Common File Formats Explained
Raster Formats
Vector Formats
Conversion Between Types
Raster to Vector
Process: Vectorization/Tracing
Converting pixels to mathematical shapes. Can be done manually or with auto-trace tools.
Limitation: Complex photos rarely convert well. Best for logos, sketches, simple graphics.
Vector to Raster
Process: Rasterization/Rendering
Converting math to pixels at a specific resolution. Happens whenever you export or display vectors.
Important: Choose correct resolution for final use (72 PPI for web, 300 PPI for print).
Common Mistakes to Avoid
Using Raster for Logos
Creating logos in Photoshop instead of Illustrator. Results in blurry logos when scaled.
Wrong Resolution for Print
Using 72 PPI web images for high-quality printing. Results in pixelated prints.
Oversized Web Images
Uploading 4000px wide images for a 800px container. Wastes bandwidth and slows sites.
Not Keeping Originals
Editing and saving JPEGs repeatedly (lossy compression). Quality degrades each time.
Professional Workflow Tips
Start with the Right Tool
Use Adobe Photoshop for raster work (photos, digital painting). Use Adobe Illustrator for vector work (logos, illustrations).
Maintain Originals
Always keep your original PSD (raster) or AI/EPS (vector) files. These are your "digital negatives" with full editing capability.
Export for Specific Use
Export copies in appropriate formats and sizes: WebP/PNG for web, TIFF/PDF for print, SVG for scalable web graphics.
Use SVG for Web Graphics
For logos, icons, and simple illustrations on websites, use SVG format. It's scalable, has small file sizes, and can be styled with CSS.
The Hybrid Approach
Many professional designs combine both raster and vector elements. For example:
- A brochure might have vector logos and text with raster photographs
- A website banner might combine SVG icons with JPEG background images
- An illustration might use vector lines with raster texture overlays
The key is understanding which elements should be which type and managing them appropriately.
Final Thoughts: Choosing Wisely
Understanding the difference between raster and vector isn't just technical knowledge—it's practical wisdom that affects the quality of everything you create. Raster images capture reality with all its complexity and nuance. Vector graphics create precision with mathematical perfection.
When in doubt, use Raster if:
- You're working with photographs or realistic images
- You need complex color gradients, textures, or natural effects
- The final size is fixed and known
- You're doing photo editing or digital painting
When in doubt, use Vector if:
- You're creating logos, icons, or branding elements
- The graphic needs to work at multiple sizes
- You need clean lines, solid colors, or precision
- File size needs to be small while maintaining quality
The most successful designers and developers master both types and know exactly when to use each. Start by analyzing your project's requirements: Will this need to scale? Is it photographic or graphical? Does it need printing or just screen display? Answer these questions, and you'll always choose the right tool for the job.
Questions & Discussion
Still confused about raster vs vector? Have specific questions about your project? Share below!