>Ultimately you can pick any coefficients you want, and only your eyes can judge how nice they are.

I went to a photoshop conference. There was a session on converting color to black and white. Basically at the end the presenter said you try a bunch of ways and pick the one that looks best.

(people there were really looking for the “one true way”)

I shot a lot of black and white film in college for our paper. One of my obsolete skills was thinking how an image would look in black and white while shooting, though I never understood the people who could look at a scene and decide to use a red filter..