2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204255In this note we review the problem of time delay of photons propagating in a spacetime with a metric that explicitly depends on the energy of the particles (Gravity-Rainbow approach). We show that corrections due to this approach -- which is closely related to DSR proposal -- produce for small redshifts ($z<<1$) smaller time delays than in the generic Lorentz Invariance Violating case.5 pages. This version contains two new references with respect to the published versionGeneral Relativity and Quantum Cosmologytext