How to change the background color in PDf documents? Not working for me.

[Edmund5F9C]

Using Adobe Acrobat Pro DC (Version 2021.011.20039) I followed Instructions on how to change the background colour in a PDF document. It didnt work. There are some other posts saying the same outcome.
Can anyone advise why it is not working. I want to change the colour or make the background neutral of transparent:
Here are the Instructions which I followed (I have also attached a Photo of these below)::
. Open a PDF documenrt using Adobe Acrobat Pro DC app and choose the following option: 'Edit' > 'Preferences'.. Highlight the 'Accessibility' option on left-hand side and the following window will be displayed : 'Accessibility'
Choose 'Replace Document Colours'. The options underneath now are made available, so chose the options best suited to what you want. The most useful option is 'Custom Colour' which allows a choice of colors for the background and the text.
To close the option, press the ''x' in top right-hand corner.

[try67]

Those instructions are correct, but this will only work if there's no background image in the file.

If there is, it won't affect how it looks.

Also, be aware this only changes the display of the document on the screen, and on your screen only.

It does not actually edit the file, and it can't be saved or printed.

[Edmund5F9C]

Thank you for your prompt reply. I had hoped to print out the document with a white or neutral background. But you have explained why this cannot be done with this program. You've saved me a lot of time. By any chance do you know any program (or programs) which might actually edit the file and saved it and print it (with a changed background)?

[Luke Jennings3]

If the background color is vector, or a fairly consistantly colored image, you can run a Preflight profile to find and change a specific color to white. If the background is an image with various shades in it, you will need to edit it in Photoshop.

To run a Preflight profile, go to Tools> Print Production> Preflight> Fixups (blue wrench).

Find the preflight "Map color with specified color values" and duplicate it from the small "Options" fly out menu.

Edit the duplicated profile as per the attached screen shot, the source color would be the color of your background (as indicated by the Output preview tool), the destination color would be 0,0,0,0.

Change "Apply to:" to "None", (which would actually include all vector and images that are the source color). Click the "Fix" button to run the profile. Let us know if you get stuck.