Her approach is defined by a restrained use of line and a preference for clear, descriptive marks. Unlike many of her contemporaries who used heavy shading, Pennink-Boelen maintained a lightness in her work. She stripped away the grime of ancient cathedrals to reveal the original intent of the medieval carvers. This clarity makes her illustrations feel like architectural diagrams rather than moody sketches.

Modern collectors appreciate the graphic quality of her prints. The work offers a connection to European history through a lens of clean aesthetics. These pieces function well in rooms that require a sense of structure. Her focus on individual figures provides a quiet, human element to a space while maintaining a sophisticated, academic atmosphere.