Painting Restoration

Jessica Mok5/31/05ME 122F

The Basic Steps of Painting Restoration

1. Conservation always begins with a thorough examination by a paintings conservator, followed by written reports that document the painting's present condition and make proposals for treatment. Photographs are taken before, during, and after treatment, to visually document the painting's condition and the progress of the project.

2. Treatment begins with the removal of dirt, grime, and other accretions from the varnish layer by means of aqueous solutions. Then the discolored natural resin varnish is reduced with chemicals that will not harm the original paint layers. Finally, the distracting, discolored retouching and overpainting in oils, from previous restorations, are reduced or removed.

3. The next step is to clean the reverse of the canvas of dirt, dust, and debris. Necessary repairs are made to the tacking edges, and the stretcher is adjusted ("keyed-out") to place even, proper tension on the canvas.

4. Attention now returns to the cosmetic problems. A nonyellowing, stable synthetic resin varnish is applied to the painting.

5. Losses in the paint and ground layers are filled and textured to match the surrounding original paint layers. Losses are inpainted with a stable, nonyellowing, nondiscoloring synthetic medium.

6. A protective backing board is secured to the reverse of the stretcher to keep out dirt and debris, prevent impact damage, and enhance the stretcher's structural stability. The painting is now ready to be reframed and hung in the museum's gallery.

Restoration Today…• The appearance of many paintings is degraded by dirt, smoke, oils,

etc. • Restorers and conservators face the challenge of staying true to the

original intent of the artist, meaning deciding “what to fix and what to leave alone”

• Restoration is a time-consuming process which does not guarantee success

• A trial and error approach is usually implemented, where chemical cleaning substances are applied in small regions of the painting to select the most appropriate substance to be used to clean the entire painting

• It is difficult to remove unwanted material from the surface of a painting without removing, disturbing or altering the organic dyes and pigments in the original layers

• In prior generations, damaged areas were filled in/painted over by modern-day artists

• The work of modern restorers is often reversible because they avoid using materials that form permanent bonds with the painting

Some Examples of Traditional Cleaning

Techniques• Traditional reagents/techniques used in cleaning involve: solvents,

spirits, alkalis, acids and soaps, as well as simple mechanical actions (ex. scraping with a scalpel)

• Michelangelo’s Sistine Chapel scenes were cleaned with a watery solution of baking soda and other mild ingredients

• Cotton swabs with saliva are sometimes used to dab paintings clean; the enzymes in saliva dissolve surface proteins and grime safely without harming the picture

• Compressed air can be aimed at spots of dust and grime to gently blow them away

• Japanese paper, a tough tissue handmade from mulberry bark, can be torn apart into fibers and used as a kind of “Band-aid” to hold sagging plaster and flaking paint temporarily in place during restoration; this was the process used in restoring Queen Nefertiti’s tomb in Egypt

• Mulberry Paper also is used as a vessel to apply cleaning solution to surface

A Tangent on Japanese Mulberry Paper

• Japanese mulberry paper, traditionally handmade, has special properties that have long been recognized by Western conservators

• This paper is characterized by long fiber, porosity, low weight compared to paper of equal thickness, translucence, exceptional permanence, full permeability to liquid chemicals, and low acidity

• Traditionally-made Japanese papers are truly acid-free if they are unbleached and unsized; paper produced today has pH ranging between 6.3 and 9.5

• The addition of wood chips in modern-day mulberry paper production to lower production costs adversely affects paper durability

• Different types include: Kozo (very long fiber, most commonly type used in Japan), Gampi (durable, thin, great wet strength, commonly used in gold/silver leaf), and Mitsumata (for soft/smooth papers, used in calligraphy and often combined with other types of fibers for reinforcement)

Modern Innovations in Restoration

• Applications of chemical solvent theory• Use of enzymes to remove very specific types of

materials (proteases for proteins, lipases for oils, etc.)• Laser vaporization of unwanted materials, in conjunction

with concurrent spectroscopic monitoring to identify the interface between different layers

• Digital imaging and algorithmic extrapolation to project full restoration from texture synthesis and color analysis of sample-cleaned patches

• ‘Rheo-reversible’ gels: polymer-based, solvent-containing gels that can be converted to a free-flowing fluid state for easier removal. These gels enable localized application and are non-volatile

Chemistry’s Role in Restoration

• The chemical composition of paints and pigments allows conservators to understand which cleaning methods are best

• Polarizing light microscopes analyze paint pigments, chipped off the painting, smaller than the width of a human hair

• The color, shape and size of pigment particles are analyzed, as are the optical properties of particles, such as refractive index. Additionally, infrared spectrums are compared against those of known compounds

• Solubility is the key to finding the most appropriate cleaning method; restorers try to find cleaning materials that cause the dirty layer to be more soluble than the clean layer

• Chemical solvent theory aids restorers in finding cleaning mixtures with appropriate components and strength

Background on Da Vinci’s The Last Supper (1495-1498)

• Not a true fresco; painted on the dry wall of a refractory rather than on wet plaster

• Leonardo sealed the stone wall with a layer of pitch, gesso and mastic, then painted onto the sealing layer with tempera, an innovative and revolutionary technique

• Within 20 years of its completion, the painting was already showing signs of deterioration due to Leonardo’s “innovation”; the combination of dry plaster with tempera caused the paint to flake away

• By 1556, Vasari described the painting as already “ruined”; it was so deteriorated that the figures were unrecognizable

• The work has undergone several restorations since its completion, the last of which occurred from 1978-1999

History of The Last Supper’s Damages and Restorations

• 1652- A doorway is cut through the painting; this is later filled in with bricks• 1726- 1st Restoration; M. Bellotti fills in missing sections with oil paint and

varnishes the finished product• 1770- 2nd Restoration. G. Mazza strips off Bellotti’s work and repaints most

of the painting, redoing 10 of the 13 faces before being stopped by public outrage

• 1821- 3rd Restoration. S. Barezzi called in to detach the painting from its wall to move it to a safer location; badly damages the work before he realizes that it is not a fresco. Attempts to reattach damaged sections with glue

• 1901-1908- Cleaning by L. Cavenaghi• 1924- Cleaning by O. Silvestri; Silvestri stabilizes some parts of the fresco

with stucco reinforcement• 1943- Refractory struck by a bomb; possible damage from bomb splinters

and vibrations• 1951-1954- Cleaning/Reinforcement with shellac by M. Pelliccioli• 1978-1999- Major restoration by P.B. Barcilon to permanently stablize

painting and reverse damages; refractory turned into a sealed, climate controlled environment, unrestorable parts re-painted with subtle watercolors

Details on the 1978-1999

Restoration• Primary Goal: Stop further deterioration. Past re-painting was

eating away at Leonardo’s original paint, and areas that were flaking were taking original paint with it

• Smog, mildew, glue, and repaint had accumulated on the painting’s surface; IR enabled restorers to see the original painting beneath these layers

• Microscopic pictures magnified areas of the paintings; sonar and radar surveys gave information about the elastic and structural characteristics of the masonry and wall upon which the painting was affixed, and mini-TV cameras inserted in the boreholes provided information about cracks and cavities

• An area of only the size of a postage stamp was cleaned every day for 21 years

The Last Supper (Before Restoration)

The Last Supper(After 1978-1999 Restoration)

Jesus

Before Restoration During Restoration After Restoration

Philip

Before Restoration During Restoration After Restoration

John

Before Restoration During Restoration After Restoration

Hand of Thaddeus

Before Restoration After Restoration

Works Cited1. The Last Supper (Leonardo). 9 May 2005. Art History Club. 29 Mar. 2005.

<http://www.arthistoryclub.com/art_history/The_Last_Supper_by_Da_Vinci>2. The Japanese Paper Place. “About Washi.”

<http://www.japanesepaperplace.com/about_jap_paper/about_washi.htm>3. The Minneapolis Institute of

Arts.<http://www.artsmia.org/restoration-online/guercino/treatment-steps.cfm>4. Barni, Mauro; Bartolini, Franco; and Cappellini, Vito. “Image Processing for Virtual

Restoration of Artworks.” IEEE Multimedia. (April-June 2000): 34-37. 29 Mar. 2005. <http://ieeexplore.ieee.org/iel5/93/18442/00848424.pdf>

5. Bianco, Luigi. 8 May 2001. Computing and the Humanities, University of Pennsylvania. 29 Mar. 2005. <http://ccat.sas.upenn.edu/~lbianco/project/restoration.html>

6. Erhardt, David. “The Art of Restoration.” Nature, Vol. 431. (23 Sept. 2004): 410-411. 29 Mar. 2005. <http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v431/n7007/full/431410a_fs.html&content_filetype=pdf>

7. Matteoli, Lorenzo. “Leonardo Da Vinci.” University of Western Australia Extension. January 2005.” <http://members.iinet.net.au/~matteoli/html/Articles/Leonardo4.html>

8. Murphy, Sue Beauman and Rempel, Siegfried. “A Study of the Quality of Japanese Papers Used in Conservation. The Book and Paper Group Annual, Vol. 4. (1985). 29 Mar. 2005. <http://aic.stanford.edu/sg/bpg/annual/v04/bp04-08.html>

9. Pappas, Michail and Pitas, Ioannis. “Digital Color Restoration of Old Paintings.” IEEE Transations on Image Processing, Vol. 9. Issue 2 (2000): 291. 29 Mar. 2005. <http://ieeexplore.ieee.org/iel5/83/17803/00821745.pdf?arnumber=821745>

10. Rist, Curtis. “How to Heal a Masterpiece.” Discover Magazine, Vol 20. No. 04 (April 1999). 30 Mar. 2005. <www.discover.com/issues/apr-99/features/masterpiece/?page=2>, <www.discover.com/issues/apr-99/features/masterpiece/?page=1>