This masterclass will introduce participants to the fundamentals of mordançage. Mordançage is an obscure darkroom technique developed in the 1970s by French photographer Jean-Pierre Sudre, which evolved from the 19th-century bleach etching process. In the first part of the workshop, we will learn how to produce gelatin silver prints in the darkroom that are best suited to mordançage. We will discuss the chemistry components, the bleaching and developing steps, and the emulsion handling techniques to add veils and textures to each print using the mordançage chemistry. In the second part of the workshop, we will learn an innovative technique to apply mordançage chemistry to colour negative film. Participants will gain a thorough understanding of this haunting process and leave the workshop with the knowledge to create fully realised mordançage prints and negatives.