To convert to a black-and-white shot in Adobe Camera Raw, click the HSL/Grayscale icon below the histogram.
Tick Convert to Grayscale, then use the sliders to hone the results. Drag the individual sliders to the right or left to alter how individual tones appear, enhancing each one in turn or knocking back any that are too prominent.
Next, zoom in and check to see whether you’ve introduced additional noise with any of the adjustments, returning to the Detail menu to compensate if necessary using the noise reduction sliders.
To finish off, add a vignette by selecting the Effects (Fx) tab and using the Post Crop Vignetting sliders to darken the edges and keep the attention on the centre of the frame.