How did black-letter type develop from Carolingian minuscule handwriting?

Black-letter type evolved from Carolingian minuscule through a gradual process of stylistic transformation that began in the 12th century.12

Originally, Carolingian minuscule was characterized by clear, round, and widely spaced letterforms. However, as scribes sought to save time and materials, they began to compress the letters laterally. This shift was influenced by changes in pen technique; scribes began holding the pen shaft to the side rather than pointing it over the shoulder, which necessitated cutting the nib obliquely to produce a thicker, more prominent vertical stroke (minim).314

Over time, these modifications led to the following developments:
* Compression and Angularity: By the 11th century, the once-round curves of Carolingian letters were increasingly replaced by sharp angles and points.12
* Increased Density: The letters became thinner, while the strokes themselves were made thicker, creating a dense, dark appearance on the page often described as resembling woven fabric, or textura.14
* Standardization: By the 15th century, this evolution resulted in the formal, square-text Gothic letter, which served as the primary model for early movable type.1