@laureth
howeverythingworks.org/page1.php?QNum=1529
This only applies to tests graded by Scantron devices and that only became common practice in the late seventies. The use of HB or #2 pencils in school tests dates back to the early part of the last century. The Dept. Education requirement was for a pencil soft enough to be easily legible, but hard enough not to have the lead break with light pressure. In the first couple of years of grade school in ancient times (when I attended) you were only able to use pencils – ink was reserved for bigger kids,