Frequently you’ll find highly textured subjects a natural for black & white conversion. The absence of color seems to enhance the texture, especially if the subject to monochromatic from the start.
Stark shadows in relief against a bright background can also be enhanced with B&W conversion, such as with these two images:
But not all textured, monochromatic images benefit from such treatment. Occasionally you’ll stumble across the exception, in which just a hint of color makes the image pop. Below is an example of what I mean, where just a hint of exposed red brick and a rusty discoloration beneath the wooden doors serve to contrast an otherwise monochromatic composition.
Taking the shot above and converting it to B&W, even after filtering for green to darken the reddish brick, just doesn’t have the same oomph, in my view:
Taking the same image and converting after red filtering makes for an even blander translation:
Color filtering for B&W photographs, you ask? Yes. We’ve had a lesson or two (or three) on this before: