The significant lightweight engineering potential of advanced high strength steels (AHSS) is limited by its moderate formability and altered failure behavior compared to mild steel grades. Especially bendability is crucial in automotive applications. The failure phenomena and underlying damage mechanisms in small curvature bending of AHSS are revealed in this work. A new characterization approach based on optical strain measurement is presented to comprehensively identify the failure stages, critical strains and bending angles in a user-independent manner. The novel approach is generalized and broadly applicable. Thus it gives a prerequisite for improved and material specific industrial process design in future.