The Restoration of the Last Judgment
The Process
The restoration of Michelangelo’s Last Judgment took place after the ceiling of the Sistine Chapel was restored. A convention was held in 1990 to discuss this cleaning and the restorers got to work immediately after.
The first step in the process involved lab tests and chemical tests on the fresco to gather data. Experts were called in to aid in this process, some of which included Carlo Pietrangeli, Director of Vatican Museums and Restoration, and Pasquale Rotondo, former director of the Istituto Centrale de Restauro and consultant for the restoration.
Next the team dismantled the scaffolding that had been used to clean the ceiling just a few months earlier. This took place in January of 1990. The new scaffolding that had to be built specifically for the Last Judgment painting included 7 work platforms and took from February to March to complete.
Next the restorers had to photograph the entire fresco under ultraviolet light. This took from April 24th until July 31st to complete.
Once all the photography was finished, the painting underwent more lab tests, this time on the fresco as a whole. This was done to get an overall sense of its condition at this point in the restoration process.
It was then time for the physical cleaning and the method used was based on two main goals. The first was to correctly adapt to the different conditions of individual parts of the fresco. Due to the amount of time since Michelangelo painted the Last Judgment, the surface conditions vary throughout. The point was to refrain from changing the degree of
cleaning while still bringing all parts together on the same level. The second goal was to reach this level gradually so that it was possible to leave behind some foreign matter, if need be, to even out the painting.
The first part of the cleaning procedure was to wash the entire fresco with distilled water and then again with a water and ammonium carbonate solution. That needed one day to fully dry until being applied again, but this time through four layers of Japanese paper. Once the paper was removed, the restorers washed it with a small sterilized sponge soaked in that solution. This method worked wonderfully on the figures in the painting, but had to be slightly altered to give the sky the same effect. This time the restoring team applied the ammonium carbonate for a shorter amount of time and blotted the surface with a water-soaked sponge. The pigment could not be cleaned with a brush, so blotting removed any foreign matter from the sky without friction.
The areas that were previously painted a secco ("dry" painting) were cleaned the same way as the sky. These are the portions of the fresco that were painted on years after the completion of the Last Judgment; mostly loin cloths that cover parts that were long ago deemed inappropriate. The retouchings were removed first with special solvents and tiny brushes.
Surprisingly there was no protective layer applied on top of the fresco to maintain the work that the restorers did. The supervisors decided that it was better to leave Michelangelo's original products on the fabric rather than cover it with foreign, perishable material. They did, however, design a filtration system in the Sistine Chapel to benefit both the Last Judgment and the ceiling. It regulates the climate within the Chapel by placing sensors on all the walls as well as the ceiling. This monitoring system, built in 1994, completed the restoration of the Last Judgment which completed that of the Sistine Chapel as a whole.
Detail of a group of the elect, before and after restoration
Types of Laboratory Tests
The first kinds of tests the restorers performed were microbiological tests to search the fresco for fungi, bacteria, and yeasts, especially on the upper part of the wall. A team from the University of Rome was called in to complete this task. One of the other methods of testing was a colorimetric measurement which was used to evaluate the chromatic variations of the wall that could have been a result of any kind of foreign matter on the original painting. This was also done by an outside team that had to be brought in. Pigment analysis is a different kind of test that involves atomic absorption spectrophotometry. This can only be done with a chemical flame and a carbon furnace. In order to gain any potentially important information other than through these three tests, sections of the fresco were examined under a microscope.
Lab tests in progress for the cleaning of specific parts of the fresco
The Palette
Whites: Lime white (hydrated calcium carbonate)
Yellows: Yellow ochers of various tones (earth silicates more or less rich with hydrated ferrous oxide)
Browns: Umber (ferrous oxide and manganese dioxide)
Blues: Lapis lazuli (aluminum and sodium silicates containing sulphur); Azurite (basic copper carbonate), in small quanitities
Reds: Red ocher (anhydrous ferrous oxide)
Greens: Terre verte (ferrous silicates); Malachite (basic copper carbonate), present only in St. Catherine's dress
Blacks: Vine black (black obtained from burning grapevines)
Resources Consulted:
Partridge, Loren, Mancinelli, Fabrizio, and Colalucci, Gianluigi. Michelangelo the Last Judgment: A Glorious Restoration. New York: Harry N. Abrams Inc., 1997.
Pietrangeli, Carlo, Michael Hirst, and Gianluigi Colalucci, eds. The Sistine Chapel: A Glorious Restoration. Italy: Harry N Abrams, 1994.
Giacometti, Massimo. The Sistine Chapel. New York: Harmony, 1986.
, Dan. "Will Michelangelo’s Vision Speak to Cardinals, as John Paul Predicted?" The Catholic Voice. 2005<http://www.catholicvoiceoakland.org/todaysnewsarchives/todaysnewsApr1605.htm#today3>.
Pictures obtained from:
Partridge, Loren, Mancinelli, Fabrizio, and Colalucci, Gianluigi. Michelangelo the Last Judgment: A Glorious Restoration. New York: Harry N. Abrams Inc., 1997.Pietrangeli, Carlo, Michael Hirst, and Gianluigi Colalucci, eds. The Sistine Chapel: A Glorious Restoration. Italy: Harry N Abrams, 1994.
