Sometimes you can convert a colour picture to black and white and it just works and other times it just looks a little muddy. What I like to do is the use the dodge and burn tools to add a little contrast to the faces just to give them a little something extra. Here’ the colour image I started with.
And here’s a straight conversion with my Fresh Black and White action. It looks ok but I think it could be better to make his eyes more of a focus.
Flatten you image and click on the dodge tool in the toolbar and set the range to highlights. I have it set to an exposure of 6%. Much higher and it would start to blow out the highlights so experiment yourself but keep the numbers low. Rub over the areas of the picture you would like the highlights picked up a little.
Do the same with the burn tool but this time set the range to Shadows. The more you paint the darker the shadows will get to judge it by eye and make sure nothing is clipped or blown by checking your histogram afterwards.
And here is the final picture with just the face affected. You can see how the face is more contrasted without losing detail.