Can i convert a pdf to low size pdf without losing the exact color profile using ghostscript

Question

I am using the below settings to convert a high resolution pdf to a low dpi but I can see that the color changes in the output file.

"-sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dQUIET -oC:\test5\pdfTestFinalToPdflow.pdf C:\test\xyz.pdf"

I'm losing the colors which I don't want to. Can I keep the same colors and still reduce file size.

Or should I stick to /prepress as it does reduce the filesize in my case which is from 5mb to 2mb

"-sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress -dQUIET -oC:\test5\pdfTestFinalToPdfHigh.pdf C:\test\xyz.pdf"

I'm a newbie in the art of ghostscript and any help would be greatly appreciated

Answer 1

Well you could start by not using the /screen canned settings. These anned setups include a large number of settings, many of which may not be appropriate.

In your case I imagine its the ColorConversionStrategy, in the /screen case that is set to RGB, so all content will be converted into RGB space. While you could use the colour management to do a good job of that, you'll have to set up ICC profiles, and there's no evidence of you doing so in your command line.

The individual controls are documented, and the distiller settings match the Adobe Acrobat settings, where they differ that is documented.

So rather than produce a new PDF file where a load of unknown things have been done to the input, try just changing the controls you want. Like the image downsampling for example.