Among the different possibilities to generate a beam conjugated to an incident one, saturable absorption is presented as the most simple method. Recently, several authors have, however, described the use of Xanthene dyes (XD) as good candidates for degenerate four-wave mixing at low laser powers. This paper deals with the description of the systematic study of six XD compounds: Fluorescein and five of its halogenated derivatives. The rigid matrix in which the dyes are embedded is made of a poly(vinyl alcohol) film prepared from an aqueous solution. The measurements of the saturation intensities as well as reflectivities of phase conjugation mirrors are obtained by an original experimental set-up connected to a data acquisition system. Different parameters such as sample thickness, optical density or beam ratios are investigated. The results for the six dyes are presented and compared.