The motion and long-range interactions of dislocations are essential to understand the mechanical, electronic and thermal properties of materials, but their dynamics are difficult to measure. While transmission electron microscopy (TEM) has imaged dislocations for half a century, its limited field of view and sample thicknesses may not be representative of bulk phenomena. To understand the “stochastic” dislocation dynamics in bulk crystals that govern their properties and dynamics, dark field X-ray microscope (DFXM) has been developed to image deep subsurface dislocations. By imaging along an X-ray diffracted beam with an objective lens, DFXM images lattice distortions hundreds of micrometers beneath the surface of crystalline materials – mapping hierarchical structures of dislocations. While today’s DFXM can effectively map the line vector of dislocations, it still cannot quantify the Burgers vector required to understand dislocation interactions, structures, and energies. Our study formulates a theoretical model to establish the theory behind how DFXM images map information to deduce the Burgers vector of dislocations. By revisiting the “invisibility criteria” from TEM theory, we re-solve this formalism and extend it to the ray-optics models developed for DFXM in order to evaluate how the images acquired from different scans about a single {hkl} diffraction peak encode the Burgers vector within them. This work advances our understanding of DFXM to establish its capabilities to connect bulk experiments to dislocation theory and mechanics.