Micro Climates and Moisture Induced Damage to Paintings

Marion F. Mecklenburg

Smithsonian Museum Conservation Institute Washington, D.C.

Copenhagen, November 19, 2007 The Smithsonian Institution is the National Museum System of the United States

James Smithson's Gift "I then bequeath the whole of my property... to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase & diffusion of knowledge..." James Smithson (1765-1829) The Smithsonian Institution has 19 Museums and 9 Research Centers including:

The Anacostia Community Museum The Arts and Industries Building Cooper-Hewitt National design Museum Free Gallery of Art and Arthur M. Sackler Gallery Hirshhorn Museum and Sculpture Garden National air and Space Museum and the Udvar-Hazy Center National Museum of African Art National Museum of American History, Behring Center National Museum of Natural History National Museum of the American Indian National Portrait Gallery National Postal Museum National Zoological Park Smithsonian American art Museum and its Renwick Gallery As such the Smithsonian maintains over 600 buildings with 33 “monumental” buildings.

Maintaining the buildings is also a “monumental” task

There are a total of 8,426,000 square feet (782,775 sq. m)

The total energy costs for FY 2006 was $32,800,000 US.

And the tightly controlled environments in the buildings was causing considerable damage. The Smithsonian “Castle” This is the first building for the Smithsonian institution (1855) But there were growing problems with the buildings resulting from tightly controlled interior environments. The National Museum of American History, c 1960’s The National Museum of American History, c 1960’s Condensing moisture due to high relative humidity (50%) In the wintertime. The Hirshhorn Museum, 1970’s The Hirshhorn Museum, 1970’s

Moisture penetration through wall systems. The leaks are a result of condensing moisture in the wall in the wintertime and structural settlement over the balcony area. 75mm Prefabricated Concrete Panels 25mm Plaster

829mm Reinforced Concrete

96mm Air Space 75mm Air Space 21C 18.3C 11.6C 10.1C

2.7C Dew Point 0C -2.7C -4.4C -9.4C

Outer Wall of the Hirshhorn Museum 812 mm concrete 101mm air structure space 76 mm concrete 76mm air panel Water Condenses here space and runs inside and outside Dry wall the building

Air spaces Gaps in the seam between the floor and the drywall

Structural Flooring System Outer Wall No insulation Leaks

Gaps in the seam between the ceiling and the drywall

Hirshhorn Museum Outer Walls These were not the only buildings with problems due to the environmental control The Renwick Gallery, c. 1860 The Renwick Gallery, c. 1860 Moisture condensation on the walls in cold winters. Indoor ambient relative humidity was 50%. In the hot summertime RH drop to 35% behind the painting. The damage potential is significant. 19th century Italian oil on canvas.

Photos courtesy of Melvin J. Wachowiak The composite behavior of restrained canvas paintings in an environment of changing relative humidity. Restrained testing and the principle of superposition. All layers of canvas painting are under stress nearly all of the time. 3

Linen canvases develop high forces ) 2.5 m at high levels of relative humidity. m It will shrink severely if loose. 5

2 2 / N ( Fairly constant level of stress h t 1.5 d Fill i w / e 1 c r o Warp F 0.5

0 0 20 40 60 80 100 Relative Humidity (%) 248 Linen 3

) 2.5 m m 5

2 2 / N

( Fill h t 1.5 d i w /

e 1 c r Warp o

F 0.5

0 0 20 40 60 80 100 Relative Humidity (%) 10

) Hide glue, 0.012mm thick films

m 8 m

5 No strength at all 2 / 6 N ( (The maximum stress h t

d level is 27 MPa) i 4 w / e c r o

F 2

0 0 20 40 60 80 100 Relative Humidity (%) 2.5

13 Year old Lead White,

) 2

m 0.13 mmm thick, (max stress = 0.65MPa) m 5

2 1.5 / N (

h 13 Year old Naples Yellow, t 1 d i 0.16 mm thick w / e 0.5 c r o F 0

-0.5 0 20 40 60 80 100 Relative humidity (%) 10

Hide glue ) 8 m m 5 2 / 6 N ( h t d i 4 8800 linen fill w / e c

r Paints 8800 linen warp o 2 F

0 0 20 40 60 80 100 Relative Humidity (%) Unknown American Portrait by Duncan Smith (1906) 14 Warp ) 12 m m

5 10 Fill 2 / N ( 8 h t d i 6 w / e c 4 r o F 2

0 0 20 40 60 80 100 Relative Humidity (%) Oil painting, 1990 American, artist unknown 25 Start of the test Fill Fill, 1st cycle

) Fill, 2nd cycle m 20 warp, 1st cycle m Warp 5 warp, 2nd cycle 2 /

N 15 ( h t d i 10 w / e c r o 5 F

0 0 20 40 60 80 100 Relative Humidity (%) Cycling painting in large RH ranges.

C.L. Buckling from loose keys and over expansion

Cracking from low RH

Key out cracking 10 Hide glue ) 8 m m 5 2 /

N 6 ( h t d i

w 4 / 8800 linen warp e c r Paints o 8800 linen fill F 2

0 0 20 40 60 80 100 Relative Humidity (%) b

High moisture damage The strength of the oil paints made with different pigments

Paints tested at 48% RH, 23 C 5 Cold pressed linseed oil Zinc oxide Basic lead carbonate 4 14.5 years 14.25 years ) a P 3 M ( Titanium white s s

e 14.5 Years r 2 t Malachite S 12.25 years 1 Yellow ochre, 12.25 years Raw umber, 12.25 years 0 0 0.01 0.02 0.03 0.04 0.05 Strain The effects of humidity on the different pigments

Earth Colors

19th Cent. Italian, oil on canvas. Damage is due to high moisture levels White lead Correcting the problems

•Reset the museum environment, lower the RH in the wintertime to 37% RH - 40% RH

•Provide backing boards to all paintings

•Provide a 25mm - 50mm airspace behind all paintings on the inside of exterior walls. Benefits of the changes

•Maintain the collection stability

•Lower building maintenance costs

•Lower energy consumption Contact information

Marion F. Mecklenburg, Ph.D. Senior Research Scientist Smithsonian Institution Museum Conservation Institute Museum Support Center, Room F 2013 4210 Silver Hill Road Suitland, MD 20746-2863 Phone 301-238-1241 Fax 301-238-3709 e-mail [email protected]