
Want your anime/colored image to have a touch of black-and-white manga? Well there's more than just grayscale, here's how!
First I'll be using this image from the series
Kirsche.

First, set that layer to grayscale. To do so, go to Image > Adjustments > Desaturate.

Duplicate that layer, set the layer mode to Overlay. Sharpen twice. (Filter > Sharpen > Sharpen)

Duplicate the base (now desaturated), drag to top, set to Soft Light.

Still on that layer, go to Image > Adjustments > Brightness/Contrast.

Use the following settings (Brightness + 50, Contrast - 100).

And there you have it! ;]