Redshifts in which the different Euclid, IRAC, and ground-based filters trace the optical (red bars) or UV (blue bars) continuum. The grey shaded area indicates the redshift range in which we have at least four filters to derive the slopes necessary to select LRDs. The hatched area indicates the redshift range covered without IRAC. The first two bars, separated by a horizontal solid black line, indicate the redshift range in which at least two JWST NIRCam broad-band filters trace the rest-frame optical or UV continuum.