Photometry – measuring the fluxes of sources – is one of the most fundamental operations in astrophysics. It therefore underlies experiments like determining distances or photometric redshifts to objects, impacts our understanding of their underlying physics, and at a population level, limits how well we can infer the Hubble constant, or the equation of state of dark energy. Getting fluxes wrong by a couple of percent can move galaxies from a photo-z of 13 to a much more modest 4. I will review how we currently determine fluxes, and what the drawbacks of existing methods. I will introduce a network of faint DA white dwarf that we have studies using over a 150 HST orbits and hours of ground-based spectroscopy to establish the most precise network of photometric standards ever down to V=19.5 mag, with agreement between models and data at the 4 millimag level. I’ll describe how we are moving these white dwarfs to building all-sky photometric catalogs, bootstrapping wide-field surveys, and how these improvements will impact the next generation of survey experiments, particularly the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope.