I am presently been working with and collaging technical plan drawings on velum and drawings and facsimiles of designs, many of which have been hand coloured. All are the output of Gerhard Hamm 1935-2016 (my father in law) an industrial designer and goldsmith of Leonberg, Baden-Württemberg, Germany, who produced these from the 1950s, up until the mid 1990s.
These drawing come from the time before CAD and are part of a lost heritage of design practices as I think very few designers or architects use paper or velum and pencils and inks nowadays. Its my intention in putting these collages together to keep the memory of the skill and craft of this soon to be forgotten art alive in some way.