A repo for small PDF utilities.

Convert PDF RGB to only-Black

This will convert an RGB PDF (even if it appears only black) to input-K.pdf.

./color_convert.sh black input.pdf input-K.pdf

Convert PDF from RGB to CMYK

Dependencies:

• gs (Ghostscript)
• pdftops

This will convert a PDF to input-cmyk.pdf.

Usage:

./rgb2cmyk.sh input.pdf

Overprint

If you need overprint, This command will convert a PDF to input-cmyk-op.pdf :

./rgb2cmyk.sh input.pdf overprint

Combine PDFs having different color modes

Dependencies:

• gs (Ghostscript)
• pdftk (for multistamp)

This will convert each input PDF file to the corresponding color mode (black, cmyk or spot color), then combine the resulting files on top of each other.

Example

Overlaying a black PDF, a coloured PDF and a spot color PDF (this one is exported full-black and is colored by the script):

./color_convert.sh black,cmyk,spot-PANTONE 705 U-0.9 0.1 0.5 0.1 input_layer1.pdf,input_layer2.pdf,input_layer3.pdf output.pdf

Check color separations

Dependencies:

• gs (Ghostscript)
• magick (ImageMagick)

This makes black and white images of each CMYK plates and makes a small HTML page to preview the plates. It will output blank plates if your PDF is in RGB.

Usage:

./colorSeparation.sh input-cmyk.pdf

Web interface for coloured preview of each plate:

By zooming out, you can see several pages at the same time: