2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12556I review the effects of dust obscuration in galaxies at both low and high redshifts, and briefly discuss a method to remove dust reddening from the emerging light of star-forming galaxies. I also analyze the evolution of the dust opacity in galaxies as a function of redshift, and discuss its effect on the observed UV-optical light. The quantitative corrections for dust obscuration given here allow one to recover the intrinsic value of the global star formation at different cosmological times.Latex, 3 encapsulated postscript Figures, uses moriond.sty special macro. Invited review at the XXXIIIrd Recontres de Moriond on Dwarf Galaxies and Cosmology, held in Les Arcs, France, March 14-21, 1998. Proceedings Editors: T.X. Thuan, C. Balkowski, V. Cayatte, and J. Tran Thanh VanAstrophysicstext