pdf-tools

name	pdf-tools
description	Apply when converting, processing, or analyzing PDF files

PDF Tools Guide

Rules and usage for PDF tools in [WORKSPACE_FOLDER]/../.tools/.

MUST-NOT-FORGET

• Check existing conversions before converting
• Default output: ../.tools/_pdf_to_jpg_converted/[PDF_FILENAME]/
• Use 120 DPI for screen/transcription, 300 DPI for OCR
• Two-pass downsizing: Ghostscript (images) then QPDF (structure)

PDF to JPG Conversion

Script: DevSystemV2/skills/pdf-tools/convert-pdf-to-jpg.py

Converts PDF pages to JPG images for vision analysis.

Usage:

python DevSystemV2/skills/pdf-tools/convert-pdf-to-jpg.py <input.pdf> [--output <dir>] [--dpi <dpi>] [--pages <range>]

Examples:

python DevSystemV2/skills/pdf-tools/convert-pdf-to-jpg.py invoice.pdf
python DevSystemV2/skills/pdf-tools/convert-pdf-to-jpg.py invoice.pdf --dpi 200 --pages 1-2
python DevSystemV2/skills/pdf-tools/convert-pdf-to-jpg.py invoice.pdf --pages 1

Output Convention:

• Default output: ../.tools/_pdf_to_jpg_converted/[PDF_FILENAME]/
• Each PDF gets its own subfolder named after the PDF file (without extension)
• Files named: [PDF_FILENAME]_page001.jpg, [PDF_FILENAME]_page002.jpg, etc.
• Check for existing subfolder to skip re-conversion

Parameters:

• --output: Output directory (default: ../.tools/_pdf_to_jpg_converted/)
• --dpi: Resolution (default: 120)
• --pages: Page range - "1", "1-3", or "all" (default: all)

7-Zip CLI Tools

Location: ../.tools/7z/

7-Zip is required to extract Ghostscript from its NSIS installer. The standalone 7za.exe cannot extract NSIS archives.

Extract archive

& "../.tools/7z/7z.exe" x -y -o"output_folder" "archive.zip"

Extract NSIS installer (like Ghostscript)

& "../.tools/7z/7z.exe" x -y -o"output_folder" "installer.exe"

List archive contents

& "../.tools/7z/7z.exe" l "archive.zip"

Poppler CLI Tools

Location: ../.tools/poppler/Library/bin/

pdftoppm - PDF to Image

& "../.tools/poppler/Library/bin/pdftoppm.exe" -jpeg -r 150 "input.pdf" "output_prefix"

pdftotext - Extract Text

& "../.tools/poppler/Library/bin/pdftotext.exe" "input.pdf" "output.txt"

pdfinfo - Get PDF Metadata

& "../.tools/poppler/Library/bin/pdfinfo.exe" "input.pdf"

pdfseparate - Split PDF Pages

& "../.tools/poppler/Library/bin/pdfseparate.exe" "input.pdf" "output_%d.pdf"

pdfunite - Merge PDFs

& "../.tools/poppler/Library/bin/pdfunite.exe" "page1.pdf" "page2.pdf" "merged.pdf"

QPDF CLI Tools

Location: ../.tools/qpdf/bin/

Merge PDFs

& "../.tools/qpdf/bin/qpdf.exe" --empty --pages file1.pdf file2.pdf -- merged.pdf

Split PDF (extract pages)

& "../.tools/qpdf/bin/qpdf.exe" input.pdf --pages . 1-5 -- output.pdf

Decrypt PDF

& "../.tools/qpdf/bin/qpdf.exe" --decrypt --password=secret encrypted.pdf decrypted.pdf

Repair PDF

& "../.tools/qpdf/bin/qpdf.exe" --replace-input damaged.pdf

Linearize (optimize for web)

& "../.tools/qpdf/bin/qpdf.exe" --linearize input.pdf output.pdf

Smart PDF Compression Script

Script: DevSystemV2/skills/pdf-tools/compress-pdf.py

Intelligent PDF compression that analyzes content and applies optimal strategy.

Usage:

python DevSystemV2/skills/pdf-tools/compress-pdf.py <input.pdf> [--compression high|medium|low] [--output output.pdf]

Examples:

python DevSystemV2/skills/pdf-tools/compress-pdf.py report.pdf
python DevSystemV2/skills/pdf-tools/compress-pdf.py report.pdf --compression high
python DevSystemV2/skills/pdf-tools/compress-pdf.py report.pdf --compression low --output archive.pdf

Compression levels:

• high: Target 50%+ reduction, aggressive (72 DPI)
• medium: Target 25%+ reduction, balanced (150 DPI)
• low: Target 10%+ reduction, preserve quality (300 DPI)

Features:

• Analyzes PDF structure (images, DPI, format, optimization status)
• Predicts compression potential before processing
• Escalates to more aggressive strategies if target not reached
• Reverts to previous result if aggressive approach shows insufficient improvement

Output: ../.tools/_pdf_output/[PDF_FILENAME]_compressed.pdf

Simple PDF Downsizing Script

Script: DevSystemV2/skills/pdf-tools/downsize-pdf-images.py

Direct Ghostscript wrapper for manual DPI control.

Usage:

python DevSystemV2/skills/pdf-tools/downsize-pdf-images.py <input.pdf> [--output <dir>] [--dpi <dpi>] [--preset <preset>]

Parameters:

• --output: Output directory (default: ../.tools/_pdf_output/)
• --dpi: Resolution (default: 150)
• --preset: Quality preset - screen (72), ebook (150), printer (300), prepress (300)

Output: ../.tools/_pdf_output/[PDF_FILENAME]_[DPI]dpi.pdf

Ghostscript CLI Tools

Location: ../.tools/gs/bin/

Compress images (downsize PDF)

& "../.tools/gs/bin/gswin64c.exe" -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dDownsampleColorImages=true -dColorImageResolution=72 -dDownsampleGrayImages=true -dGrayImageResolution=72 -dDownsampleMonoImages=true -dMonoImageResolution=72 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

Quality presets (-dPDFSETTINGS)

• /screen - 72 DPI, smallest file size
• /ebook - 150 DPI, medium quality
• /printer - 300 DPI, high quality
• /prepress - 300 DPI, color preserving

Remove all images (text only)

& "../.tools/gs/bin/gswin64c.exe" -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dFILTERIMAGE=true -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

PDF Downsizing Workflow

Two-pass workflow for maximum compression:

Pass 1: Ghostscript (image compression)

& "../.tools/gs/bin/gswin64c.exe" -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dDownsampleColorImages=true -dColorImageResolution=72 -dDownsampleGrayImages=true -dGrayImageResolution=72 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=temp.pdf input.pdf

Pass 2: QPDF (structure optimization)

& "../.tools/qpdf/bin/qpdf.exe" --linearize --object-streams=generate --stream-data=compress --compress-streams=y --optimize-images --flatten-annotations=screen temp.pdf output.pdf
Remove-Item temp.pdf

PDF Analysis

Before optimizing, analyze the PDF to understand what's consuming space.

Get PDF info

& "../.tools/poppler/Library/bin/pdfinfo.exe" "input.pdf"

List all images with details

& "../.tools/poppler/Library/bin/pdfimages.exe" -list "input.pdf"

Shows: page, dimensions, color space, compression, DPI, size. Use to determine if images can be further compressed.

Count images

& "../.tools/poppler/Library/bin/pdfimages.exe" -list "input.pdf" | Measure-Object

Optimization Strategies (by effectiveness)

Tested on 6 real-world annual reports (50-100 MB each):

High compression (>50% reduction):

• JPEG2000 at 200 DPI: 77 MB → 4.5 MB (94% with screen, 86% with ebook)
• Mixed content, not optimized: 84 MB → 34 MB (59%)
• Mixed content: 49 MB → 21 MB (57%)

Moderate compression (10-50%):

• Already optimized PDF: 47 MB → 42 MB (10%)

Low compression (<10%):

• PDF with 10552 tiny images: 58 MB → 56 MB (4%) - many small UI elements
• Image-only PDF at 115 DPI: 101 MB → 97 MB (4% at 100 DPI, 77% at 72 DPI)

Key factors affecting compression:

• Image format: JPEG2000 (jpx) compresses dramatically when converted to JPEG
• Image DPI: High DPI (200+) benefits most from downsampling
• Already optimized: PDFs marked "Optimized: yes" compress less
• Many small images: Thousands of tiny icons/UI elements resist compression

Strategy 1: Aggressive (best for large reductions)

cmd /c "& '../.tools/gs/bin/gswin64c.exe' -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dDetectDuplicateImages=true -dCompressFonts=true -dSubsetFonts=true -dConvertCMYKImagesToRGB=true -dColorImageDownsampleType=/Bicubic -dNOPAUSE -dBATCH -sOutputFile=output.pdf input.pdf"

Strategy 2: Balanced (preserves more quality)

cmd /c "& '../.tools/gs/bin/gswin64c.exe' -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dDetectDuplicateImages=true -dCompressFonts=true -dSubsetFonts=true -dConvertCMYKImagesToRGB=true -dNOPAUSE -dBATCH -sOutputFile=output.pdf input.pdf"

Strategy 3: Structure only (no quality loss)

& "../.tools/qpdf/bin/qpdf.exe" --linearize --object-streams=generate --compress-streams=y --recompress-flate input.pdf output.pdf

Key Optimization Flags

• -dDetectDuplicateImages=true - Replace duplicate images with references
• -dCompressFonts=true - Compress font data
• -dSubsetFonts=true - Include only used glyphs
• -dConvertCMYKImagesToRGB=true - Convert CMYK to RGB (smaller)
• -dColorImageDownsampleType=/Bicubic - Better quality downsampling

Best Practices

1. Analyze first: Use pdfimages -list to understand image content before optimizing
2. Check existing conversions: Before converting, check if subfolder exists in _pdf_to_jpg_converted/
3. Use appropriate DPI: 72 for web/archive, 150 for screen, 300 for print/OCR
4. Convert specific pages: Use --pages to avoid converting entire large PDFs
5. Clean up: Delete old conversions when no longer needed
6. Two-pass for maximum compression: Ghostscript (images) then QPDF (structure)

Setup

For initial installation, see SETUP.md in this skill folder.

Tool locations:

• 7-Zip: ../.tools/7z/
• Poppler: ../.tools/poppler/
• QPDF: ../.tools/qpdf/
• Ghostscript: ../.tools/gs/
• Installers: ../.tools/_installer/
• JPG output: ../.tools/_pdf_to_jpg_converted/
• PDF output: ../.tools/_pdf_output/