Change a black and white PDF to Magenta and White

[DCN00b]

Hi,

I'm trying to replace the colour black in a B&W pdf with a different colour (magenta) using a preflight fixup in Acrobat DC.

The pdf (referred to later as the first pdf) is a detailed technical drawing that was created from a microstation drawing and still retains the individual lines/components as selectable objects. This is something that I want to retain (hence not just using a photo editor).

Basically the intent is to use objects from the first pdf as a kind of object palette for editing another similar PDF (referred to later as the second pdf).

The colour change is required simply to change the colour of the objects in the first PDF, so when they're pasted into the second PDF, they are highlighted as changes to the original version of the second PDF.

I previously managed to convert the first PDF to red and white through trial and error by tweaking the advice given in the following discussion:

How to convert a PDF's Process Black to spot color

However the advice given in that discussion doesn't work "as is" and I spent a great deal of time trying different things based on that, until it eventually worked. Unfortunately though, I've since been unable to replicate it and accidentally made changes to the preflight fixup that did work and so now I'm back to square one.

Any help on this would be greatly appreciated.

Thanks.

EDIT: If anyone knows of an easier way to achieve the same result, let me know. This was just the solution I stumbled on and the only way I could find that preserves the vectors and doesn't covert it to a raster image.

[DCN00b · Accepted solution]

For anyone interested, I found a solution that works (for me at least).

I created a new Preflight Fixup, Selected the "Color spaces, spot colors, ... etc" Fixup Category, Selected the "Convert to spot color" as the type of fixup and used the "Gray (%), 0% is black" color model and selected my source ond destination colours.

I believe the issue was that it wasn't detecting the black used in the original pdf as CMYK (%): 0%, 0%, 0%, 100% or RGB (%): 0%, 0%, 0%.