A selection of colour dufex prints and postcards of paintings by the Johnstone twins, including 4 large (31cm x 49cm) prints, almost all of them published by F.J. Warren Ltd. (Hitchin, Hertfordshire). Dufex printing was a process developed by F.J. Warren in the early 20th century, and involves printing images onto aluminium foil-lined paper or cardboard, using UV formulated transparent inks, which allow the reflective shine to be retained. Engraving techniques are then used to add a range of light reflective textures to the foil. Many of the dufex prints in this collection also appear as ordinary cards in the series of Greetings Cards (JAJ/02) and some also appear as duplicate dufex prints or postcards within that series. This is noted at item level where relevant. A brief description of each picture, along with details of the artist/artists and publisher also appear at item level, with the publishers' reference numbers (where available).