In one of his short videos aimed at helping people get more out of B&W photography Keith looks at how your choice of how colours are turned into greys makes a huge difference to how the resulting B&W image looks.

Conversion from colour to B&W is explored further in:
https://youtu.be/sMP1ytLYiAE

All of Keith's B&W related content (video and articles/reviews) is listed at:
https://www.northlight-images.co.uk/digital-black-and-white-photography/