Some years ago I did a pencil line illustration for Ketchum, McLeod and Grove, an ad agency in Pittsburgh, the art director was Jim Fox, a former student of mine when I taught in Detroit.
Here is the ad layout that was sent to me.
This is my rough sketch done to establish the composition.
Here is a tighter sketch to establish the gray tones.
The finished drawing was done using a Wolf BBB carbon pencil. The black areas were done with a brush and India ink. The gray tones were added using Instantex, a transfer sheet that is available in various patterns and textures. These examples are from my book, DRAWING IN INK that was published in 1977 and is still available in used book stores in case you are interested in obtaining a copy.