Using Photo to convert color PDF into black and white only

[lewist57]

I have a PDF with several text and graphics that are in various colors (originally an AutoCAD file, that I sadly do not have access to). Apparently Adobe Acrobat cannot export the text and graphs as pure black and white; only "greyscale" conversions appear to be available.

Now Photo can easily import the PDF, but is there a procedure that can be used to convert all text and graphics to black and then export back as PDF, with  no "greyscale"?

Thanks.

Edited November 29, 2023 by lewist57
corrections

[NotMyFault]

Hi,

there are several options to convert into pure B&W:

1. using a threshold adjustment. Resolution stays same, but colors reduced to 2 values, black or white.
2. using dither to convert greyscale values into several distributed black/white pixels, givin the illusion of greyscale when looked at from a distance.

Unfortunately, Affinity cannot create pure 2 color 1-bit color depths files.

The most is using paletized export (for PNG) and choosing 2 colors. The export is still 8 bit color depth.

As far as i know, affinity cannot create PDF files with 1-bit color depth. You may need to look elsewhere.