Convert from colour to black and white all pdf pages

I just scanned an entire book, colored. I need to convert those 499 pages from colored to Black and White (not greyscale).
The method i used now is:

  • Open the pdf
  • Clicked on the image scanned
  • Propreties (on the right side), Image, Color Mode, B/W

The fact is that in this case I selected an image inside the page and I should redo this for all the 499 pages.
Any suggestion to do it with one click?

Thank you all <3

… I suggest that you repost that with the macro tag. Please include your AO / LO version and a two or three pages version of the draw document you want to convert.
Good luck, ms777

What you can do as a work-around:

  • have your PDF file “printed out” in single image pages - you could do on (Windows user can locally install the pdf24 apps - so no information is sent to the web)
  • convert (batch conversion - one step only) each picture to pure b/w on image processing app like XnView or IrfanView
  • import the bunch of images into Impress :: Foto album (check page size before!) :: link the images, don’t embed
  • export as a PDF - finished

No, but should be better than your individual method…

Maybe it would be easier to scan the book again but in B&W.