Wirtensohn, SamiSamiWirtensohnFlenner, SiljaSiljaFlennerJohn, DominikDominikJohnQi, PengPengQiDavid, ChristianChristianDavidMay, ManfredManfredMayHuber, PatrickPatrickHuberHerzog, DirkDirkHerzogTangl, StefanStefanTanglKampleitner, CarinaCarinaKampleitnerSingh, KritikaKritikaSinghKelbassa, IngomarIngomarKelbassaBekes, KatrinKatrinBekesHerzen, JuliaJuliaHerzenGreving, ImkeImkeGreving2026-03-272026-03-272025-06-20arXiv 2506.16998: (2025)https://hdl.handle.net/11420/62367Dark-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.enhttps://creativecommons.org/licenses/by/4.0/physics.opticsphysics.ins-detTechnology::600: TechnologyPreprinthttps://doi.org/10.15480/882.1691310.48550/arXiv.2506.1699810.15480/882.169132506.16998