Pencils come in a scale of hardness, from "hard" pencils, like H, to "soft," like 9B.
Decide how many hardnesses of pencil lead you want to include in your kit.
The effect of AUA on the end use performance properties of BDGDA coating namely, abrasion resistance, specular gloss at 60° angle, tubular impact resistance, pencil hardness, pendulum hardness, scratch resistance, mar resistance, stain resistance, steam resistance and cigarette burn resistance was also investigated.
In addition, pencil hardness tests revealed that the hardness of the metal mixture films on the kovar and copper substrates were 4H.
The pencil hardness test showed that the hardnesses of the dense and porous films were over 9H and 3B, respectively.
The closed-surface structure was with a 5 H pencil hardness, and approximately 2.0 GPa indent hardness in nanoindenter test.
The rough paper surface, the hardness of the pencil, the different degrees of pressure exerted on it, and the sometimes uncontrollable twitches and slips of the hand are reflected in the lines, giving the drawings an interesting tension, at least to those on Mr. Penone's meditative, rhythm-of-nature wavelength.
and pencil hardness methods.
Fig. 11 Average resistance force and pencil hardness.
