So… I have been playing with making color photographs into black and white.
There are two ways I know how to do it.
The first one you just get rid of the color information and make it grayscale. The second one is a little more complicated but pretty easy.
And you could just make it greyscale.
Or as some people say; change it to LAB, select the lightness channel, turn that greyscale, duplicate it and mix it with Soft light at about 30-40% op.

Which one do you like better?
