Originally, a simple pencil was the only tool needed to draw shaded relief. Although pencils do not yield pure black tones, using supplementary black ink can sufficiently darken the shadows on the highest mountain peaks.
The opposite end of the tonal scale exhibits a similar problem. Pure white is not achievable with pencil because even the brightest papers contain pallid tones. As a solution, adding supplementary dabs of white paint emphasizes the brightest illuminated slopes.