Art Conservation and Restoration

http://www.britannica.com/EBchecked/media/112875/A-restoration-curator-working-on-Michelangelos-David-2002

We will look at three types of art:

• Paintings• Frescoes (wall paintings)• Sculpture

Two Methods of Fresco Painting

• Buon fresco (fresco = “Fresh”)• Fresco a secco (secco = “dry”)

http://www.italianfrescoes.com/aboutus.asp

The Anatomy of a Fresco

http://www.atelier-st-andre.net/en/pages/technique/fresco_technique/fresco_definition.html

(Arriccio)

(Intonaco)

(watered down powdered pigment)

In buon fresco, the paint adheres in a chemical reaction to the wet lime plaster. Ca(OH)2 + CO2 CaCO3 + H2O

http://www.atelier-st-andre.net/en/pages/technique/fresco_technique/fresco_definition.html

In fresco a secco, the paint rides on top of the plaster surface. Pigments are stuck down using a binder or medium.

The Anatomy of a Painting• Medium or binder - Used with powdered pigment in paintings.

Size – glue from animal skin and bones. Sensitive to moisture.

Casein- very early use. From milk. Opaque, hard, insoluble, durable.

Egg – most durable. Alters little in color over time. Durable film. Emulsion of oil in water. Used by early Italian masters.

Oil –must be unsaturated to polymerize with light and oxygen to form a film. Darkens and becomes brittle, more transparent and insoluble as it ages.

The Anatomy of a Painting• Glazing – very little pigment in oil to build up

color. Used by masters in layers to add dimension (sfumato).– The Mona Lisa has up to 27 layers of glaze in some

places, each only 2 micrometers thick.

Mona LisaLeonardo da VinciLouvre, Paris, France

The Anatomy of a Painting• Varnish – Yellows and

brittles with age. – Spirit varnish easily

removable because has different solubility than mediums/binders.

– Oil varnish difficult to remove from oil paintings because same solubility.

http://www.gainsboroughproducts.com/cleaning.html

The Anatomy of a Painting

Conti, Alessandro. History of the Restoration and Conservation of Works of Art. London: Elsevier, 2007. Print.

Some Common Renaissance Pigments• Carmine - made from ground female cochineal insects

• Azurite – most popular blue in Renaissance and middle ages. Color degrades over time to green

malachite.

• Lapis Lazuli – the more expensive blue option in the renaissance and middle ages. Holds up well over time but as expensive as gold. Used for things like Christ’s robes.

http://mostbecoming.wordpress.com/category/carmine-cochineal/

http://energymuse.wordpress.com/2012/06/12/gemstone-of-the-day-5/

http://www.mineralminers.com/html/lapmins.stm

Raphael, Madonna and Child Enthroned with Saints, The Metropolitan Museum of Art

Analytical Techniques

• Microscopy– Ex/ Visible Light– Scanning Electron

• Electromagnetic Radiation– Ex/ UV light– Ex/ IR light– Ex/ X-Rays

• Spectroscopy– Ex/ Raman Spectroscopy

Visible Light Microscopy

Port-Goulphar, Belle-IleClaude Monet

Douma, M., curator. (2008). “Microscopy.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

Scanning Electron Microscopy

• A beam of electrons directed towards the paint sample. Elements with high atomic numbers (such as lead or gold) deflect more electrons and reflect brighter.

Hochleitner, B. et. al. Analysis of Paint Layers by Light Microscopy, Scanning Electron Microscopy, and Synchrotron Induced X-Ray Micro-diffraction. Presented at the Conference: Art 2002, June 2003. Antwerp, Belgium.

Analytical Techniques – Electromagnetic Radiation

Douma, M., curator. (2008). “Visible and Beyond.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

UV light – detects organic compounds

Adoration of the Magi, Unknown Artist, Trevi, Italy, 1522

UV light detects residue of a faded pigment

Douma, M., curator. (2008). “Ultraviolet (UV) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

UV light

Madonna Suckling the Child, artist of the Ferrarese School, early 16th century, oil paints on wood panel.

UV light distinguishes between older, organic varnish, and newer linseed oil varnish, indicating restoration.

Douma, M., curator. (2008). “Ultraviolet (UV) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

UV light

Life-size marble statue, Venus Genitrix, Louvre

UV light reveals that the hand is not the original

Douma, M., curator. (2008). “Ultraviolet (UV) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

IR light

Douma, M., curator. (2008). “Infrared (IR) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

IR light

Pontormo

IR light reveals the underdrawing

Douma, M., curator. (2008). “Infrared (IR) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

IR light

IR light reveals drawing techniques which can be helpful for authenticating artwork.

Douma, M., curator. (2008). “Infrared (IR) Light.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

IR light

“On the Good King” by Philodemus of Gadara. Entombed in volcanic ash from Mount Vesuvius, 79 AD.

IR light reveals writing that visible light cannot

Banerji, Robin. “Unlocking the Scrolls of Herculaneum.” BBC News Magazine 19 December, 2013: n. pag. Web. 19 December, 2013.

X-Ray Light

Whistler

X-Rays reveal structural information as well as paintings underneath paintings.

Douma, M., curator. (2008). “X-rayLight.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

Manuscript, "Concessione di Francesco Sforza alla Certosa di Pavia", 1450, State Archives of Milan

Analytical Techniques – Raman SpectroscopyEach molecule vibrates with a predictable frequency.

Douma, M., curator. (2008). “Spectroscopy.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

Analytical Techniques – Raman SpectroscopyEach molecule vibrates with a predictable frequency.

Byzantine illuminated manuscript, series of readings based on the gospel, 1220, British Library

Raman Spectroscopy proves that angels now black used to be white. Hydrogen sulfide from lamps in the library caused the lead white to blacken.

Douma, M., curator. (2008). “Spectroscopy.” In Pigments through the Ages. Retrieved December 18, 2013, from http://www.webexhibits.org/pigments/intro/ir.html

How Art AgesMethods• Humidity• Dirt• Pollution• Biological• LightEffects• Cracking – varnish cracks due to photodegradation• Flaking – humidity may cause separation between the ground and

paint layers• Blooming – cloudiness • Changes in Color – oxidation or reaction between varnish and paint.• Changes in Optical Effects

Changes in Color• Van Gogh’s yellowing flowers turning

greyish-orange. Thought first to be due to yellowing varnish but the varnish could not be removed, indicating that it had chemically reacted with the paint. The sulfate in the paint had formed ionic bonds with the lead in the varnish creating opaque anglesite. The cadmium combined with the varnish to create cadmium oxalate.

Visible Light Microscopy cross-section of a sample of yellow paint

Flowers in a Blue Vase, Van Goghhttp://www.esrf.eu/news/general/van-gogh-cds/index_html

Changes in Optical Effects

Conti, Alessandro. History of the Restoration and Conservation of Works of Art. London: Elsevier, 2007. Print.

Cleaning Paintings

• Organic solvents (originally wine) used to remove varnish. Can also remove organic pigments if too strong, making the paint brittle.

• Alkali reagents (lye or ammonia) used to remove oily substances. Can cause blooming in the paint if too strong.

Sculpture Deterioration• Especially of concern in

Venice’s marine climate, where the statues are subject to high levels of humidity and biological growth

Lazzarini, L. and J.F. Asmus. “The Application of Laser Radiation to the Cleaning of Statuary.” Bulletin of the American Institute for Conservation of Historic and Artistic Works 13.2 (1973): 39-49. JSTOR.

The laser heats the deposit to its vaporization point. The sculpture surface below reflects the

laser once the deposit is gone (due to short exposure time and high thermal conductivity).

Lazzarini, L. and J.F. Asmus. “The Application of Laser Radiation to the Cleaning of Statuary.” Bulletin of the American Institute for Conservation of Historic and Artistic Works 13.2 (1973): 39-49. JSTOR.

The Gates of Paradise in Florence underwent a 27 year restoration, including laser cleaning

Banerji, Robin. “Unlocking the Scrolls of Herculaneum.” BBC News Magazine 19 December, 2013: n. pag. Web. 19 December, 2013.