stain [stains](reagent or dye used to stain microscope specimens so as to make some structures visible) noun [UK: steɪn] [US: ˈsteɪn]
contrastenoun {m}
contrast [contrasts](difference that makes colours more or less distinguishable) noun [UK: kən.ˈtrɑːst] [US: ˈkɑːn.træst]The contrast immediately jumps out at one. = El contraste salta inmediatamente a los ojos.