Custom PDF tools

[1] PDF color convert script with Graphicsmagick(http://graphicsmagick.org)

This simple shell script can convert scanned PDF documents into monochrome(black and white), grayscale, or n-colored. This is done with the Graphicsmagick(http://graphicsmagick.org).

[FEATURES]

• Convert PDF into several color options (mono, gray, 1-)
  • (with secondary effect of shrinking PDF size, when reducing color.)
• Change DPI
• Preserve page box
• Batch processing (4 pages)

[REQUIREMENTS]

• Graphicsmagick(http://graphicsmagick.org)
• pdfseparate, pdfunite

[BASIC USAGE]

1. Install requirements
2. Download the script("pdf_color.sh")
3. Give the script permission to execute /ex/ chmod +x pdf_color.sh
4. Run the script:

• Basic usage: ./pdf_color.sh FILE_NAME COLOR_MODE INPUT_DPI OUTPUT_DPI
  • FILE_NAME: PDF file location; names with spaces should be "quoted"(?)
  • COLOR_MODE: output color options; can be mono, gray, 1, ...; default value is mono if omitted
  • INPUT_DPI: DPI of input pdf file; default value is 600 if omitted
  • OUTPUT_DPI: DPI of output pdf file; default value is 400 if omitted
• Examples:
  • Convert 400dpi PDF(sample.pdf) into 400dpi grayscale: ./pdf_color.sh sample.pdf gray 400 400
  • Convert 600dpi PDF(sample.pdf) into 400dpi 8-colored: ./pdf_color.sh sample.pdf 8

[APPENDIX] I made this script to shrink my scanned pdfs. My basic workflow is following:

1. I scan the original document(mostly books) with 600dpi in full color. In most time, a single scanned book is about 500Mb~1Gb.
2. While keeping the original file, I usually convert it into monochrome(for text-only books) or 6-colored(for colored books) for iPad. This mostly reduces the file size about 50-80%(10-50Mb).
3. Then I archive the original file on my external drives and delete it from my local drive.