I’ve also just tried following some of the PDF codes from here: https://processing.org/reference/libraries/pdf/index.html
But… for some reason it must be saving the PDF in CMYK, not RGB?
So this is how it looks when saved as a PDF…
However, it is much brighter in the window? not sure if my Mac is at fault for this.
As of yet haven’t tried adjusting the window… would this help?
Also, unfortunately the tutorial is a paid subscription so you’d be unable to follow it…