The speed of a line- I learned about the speed of the line during one of my first critiques classes at NCSA. It amazed me that it was possible to tell whether a drawn line was made quickly or slowly or with a combination of speeds.
Often calligraphers are challenged to write multiple calligraphic hands on one paper. Sometimes the challenge is to get large cracked letters. A rough paper that causes skips and cracked edges of letters with a larger broad edged pen will most likely not work for a pointed pen of any size. That is when knowing paper making history and Islamic techniques comes in handy.
Welcome back to the main stream black letter! Black letter's millennia-long history has taken a convoluted path. Its humble beginnings were as a child of carolingian, the Holy Roman Emperor Charlemagne's manuscript calligraphy. Carolingian was called lettera antiqua in admiration, by renaissance scholars. They called black letter Gothic, a slur meaning it was from the woods.