This paper proposes a new method for monitoring fatigue crack network initiation and growth based on Digital Image Correlation (DIC) , and reports on in-plane biaxial fatigue experiments with two dierent loading paths and two amplitudes on nodular graphite cast iron. The central thinned part of cross-shaped samples is observed on two scales. Regularized Digital Image Correlation (DIC) is used to measure displacement elds and to reveal DIC residuals, i.e., image dierences that cannot be accounted for with registration. The detailed strain histories are compared at dierent scales and for the dierent loading regimes. DIC and mechanical residuals, i.e., local deviations of the displacement eld from being the solution to an elastic problem, enable for the crack network detection and quantication with respect to the number of cycles. The relative damage severity and fatigue lifetime of different loading paths experiencing identical load magnitudes are analyzed for the tested material.