Fluoro-etching  

The technique was rarely used due to the harmful effect of acid and slow process of making reprints. Several drawings in this technique were made by, among others, Stanisław Wyspiański, Ferdynand Ruszczyc and Leon Wyczółkowski. 

It is an intaglio printmaking technique, a derivative of etching; drawing is also made in this technique. Drawing is prepared just like in etching – drawing is applied in a glass plate covered with wax varnish, which is later etched by hydrofluoric acid. After removal of varnish, the plate is covered by paint; then, paint is removed from the plate surface, leaving it only in etched places. Prints are made by hand. Boards made with the use of fluoro-etching technique can be distinguished by lack of tone in the background.