Understanding PDF Compression Algorithms

PDF compression relies on sophisticated algorithms to reduce file sizes while maintaining document integrity. Understanding these algorithms helps you make better decisions about compression settings and expected results.

Types of Compression

PDF compression uses several different approaches:

• Lossless compression: Reduces size without quality loss
• Lossy compression: Achieves higher compression with some quality trade-off
• Hybrid approaches: Combines both methods strategically

Image Compression Algorithms

Images typically account for the largest portion of PDF file size:

1. JPEG compression: Best for photographs and complex images
2. CCITT compression: Optimal for black and white text and line art
3. ZIP compression: Effective for images with large areas of solid color

Text and Vector Compression

Text and vector graphics use different optimization strategies:

• Font subsetting to include only used characters
• Vector path optimization
• Content stream compression
• Object reference optimization