Complex sentence: She was prominent in the early period of modern wood engraving, but her period of activity (1912-1926) reflects the lifespan of that modern black line tradition, and was clearly over before her early death.
Split into simpler sentences: She was prominent in the early period of modern wood engraving, but her work represented a dead end. Her period of activity (1912-1926) reflects the lifespan of that black line tradition, and was clearly over before her early death.