Wirtensohn, SamiSamiWirtensohnFlenner, SiljaSiljaFlennerJohn, DominikDominikJohnQi, PengPengQiDavid, ChristianChristianDavidMay, ManfredManfredMayHuber, PatrickPatrickHuberHerzog, DirkDirkHerzogTangl, StefanStefanTanglKampleitner, CarinaCarinaKampleitnerSingh, KritikaKritikaSinghKelbassa, IngomarIngomarKelbassaBekes, KatrinKatrinBekesHerzen, JuliaJuliaHerzenGreving, ImkeImkeGreving2026-05-122026-03-272026-05-08Light: Science & Applications 15: 223 (2026)https://hdl.handle.net/11420/63013Dark-field X-ray imaging visualizes structural inhomogeneities through small-angle scattering, but existing directional methods are confined to the micrometer scale. While recent advances have extended dark-field capabilities to nanoscale transmission X-ray microscopy, directional scattering retrieval - critical for characterizing anisotropic nanostructures - has remained inaccessible for imaging resolutions in the sub-micrometer scale. Here, we demonstrate the first directional dark-field setup for nanoimaging, achieving orientation mapping of scattering features below the spatial resolution limit. Our method is experimentally simple to implement with existing transmission X-ray microscopy setups. We validate its performance by successfully resolving sub-resolution test structure orientations, cross-correlating orientational changes within hierarchical nanoporous materials, and mapping the directional arrangement of hydroxyapatite nanocrystals 30 - 70 nm within human tooth enamel. By utilizing shadow regions in the optical configuration, we further extend the detectable scattering vector range, demonstrating a pathway toward size-selective dark-field imaging. This advancement enables the quantitative structural characterization of anisotropic nanomaterials, which are critical to biomineralization, advanced materials, and nanotechnology applications.en2047-75382026Naturehttps://creativecommons.org/licenses/by/4.0/physics.opticsphysics.ins-detTechnology::600: TechnologyJournal Articlehttps://doi.org/10.15480/882.1708610.1038/s41377-026-02263-z10.15480/882.17086