Sistine Chapel ceiling restoration began on 7 November 1984. The restoration complete, the chapel was re-opened to the public on 8 April 1994. The part of the restoration in the Sistine Chapel that has caused the most concern is the ceiling, painted by Michelangelo. The emergence of the brightly coloured Ancestors of Christ from the gloom sparked a reaction of fear that the processes being employed in the cleaning were too severe and removed the original intent of the artist. The problem lies in the analysis and understanding of the techniques utilised by Michelangelo, and the technical response of the restorers to
Sistine Chapel layer of animal glue and "lamp black", all of the wax, and all of the overpainted areas were contamination of one sort or another: smoke deposits, earlier restoration attempts, and painted definition by later restorers in an attempt to enliven the appearance of the work. Based on this decision, according to Arguimbau's critical reading of the restoration data that have been provided, the chemists of the restoration team decided upon a solvent that would effectively strip the ceiling down to its paint-impregnated plaster. After treatment, only that which was painted "buon fresco" would remain. The only reproduction of the Sistine