A conservation project was set up for the Codex Eyckensis, an illuminated manuscript on parchment from the 8th century. Polyvinyl chloride (PVC) membranes, applied in 1957, were removed. Different options for a new conservation plan were discussed within the framework of a supervising committee. Research in the fields of chemistry, microbiology, codicology, and conservation techniques was interpreted in an interactive way. A method for the laboratory preparation of gold beater's skin is described. Several adhesives for parchment repair were tested for their tensile strength, water vapor permeability, influence on the appearance of the materials to be adhered, and reversibility before and after aging, following two different systems. An investigation was started to check the applicability of dermal hide substance suspensions to parchment leaf casting according to strict working conditions.