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hm'rnational Biodeterioration 28 ( 1991 ) 23-35
Fungai Contamination of Oil Paintings in Japan
Mayumi Inoue lnoue Biodeterioration Laboratory, Tokyo, Japan
&
Masako Koyano Art Conservation Laboratory, Tokyo. Japan
A BSTRA CT
Japan~ climate, with several months of high temperatures, and high humidi~. '. is well suited to the growth of various kinds of fungi. The" grow not on o, on food. wood. and textiles, but also on paintings.
We have examined a varie~, of instances of deterioration caused by the growth of fungi on paintings and have isolated and identified more than a hundred o[ these fungi, Of these, the ~'pical ones are Alternaria. Clado- sporiurn, Fusarium, Aspergillus, Trichoderma and Penicillium.
Since ! 982 we have studied a fungicide-containing varnish to test its ability to inhibit fungal growth. The varnish, made from synthetic resin containing Vinyzene. a fungicide, was sprayed on about 100 paint samples. Annual observations have confirmed that it has a fungicidal effect.
This paper reports on the effect of the Vinvzene-containing varnish on paint and its utility as a fungicide.
I N T R O D U C T I O N
There is a hot and h u m i d season in Japan that is conduc ive to the growth of various fungi. Tradi t ional J apanese homes are open-st-yle houses made o f such a i r -permeable materials as wood, earth, paper, and fabric so that they provide for comfor tab le living in a h u m i d climate. However,
23 hlternational Biodeterioration 0265-3036/91/$03.50© 1991 Elsevier Science Publishers Ltd, England. Printed in Great Britain.
24 Mavumi Inoue. Masako Kovano
new buildings are built mainly of concrete, a luminum, and glass which means that moisture is apt to collect inside, resulting in fungal hazards. Reports of damage to oil paintings caused by fungi are increasing every year. The discolorat ion and decomposi t ion of oil paint ings caused by fungi is permanent . It is either a decompos i t ion of the paint media or a discoloration of the canvas. The latter resulting in violet, brown or black stains. The discolorat ion and decomposi t ion is also of a progressive nature: paintings will cont inue to deteriorate under certain environ- mental conditions.
Of the measures taken to protect oil paintings from fungal hazards, the most desirable is to control the temperature and humidity, of the env i ronment su r round ing the paintings. The ideal condi t ion in a m u s e u m is set at RH 50-55% and 18-20°C. at which the growth of fungi can be prevented. However, in the case of large oil paint ings and oil paintings kept in a wooden structure, the control of the env i ronment using an air condi t ioner is almost impossible.
If the use of a safe fungicide on oil paint ings was made possible, we could save many oil paintings from the hazards o f fungi. In Japan penta chloro phenol (PCP) and 2-(4 thiazolyl)-benezimidazal (TBZ, Merck Index, p. !167, 9th edn, 1976) have been used as fungicides for oil paintings. Al though both are effective, they have problems. The fungicide PCP turns brown after some years, while TBZ does not completely dissolve in a solvent.
For the past 10 years we have collected and identified fungi growing on oil paint ings in Japan. More than 100 cases were studied, with the result that we now have an unders tand ing of fungi that grow on oil paint ings in Japan, in terms of what they are and what they do.
In an effort to counteract the fungi, and as a test case, we mixed varnish with Vinyzene, which is chemical ly stable, and which supposedly remains t ransparent when mixed with varnish. We sprayed the mixture on oil paint samples 7 years ago and observed the results. This paper is a report on those results as well as on our general examina t ion of the fungi growing on oil paint ings in Japan. We would like to point out that this paper is not mean t to be a r ecommenda t ion for the use of any varnish product that contains a fungicide.
E X P E R I M E N T A L
Oil paintings selected for this study
Samples of fungi were taken from 40 oil paint ings that were accepted for conservat ion work at the Art Conservat ion Laboratory in Tokyo from
Fungal contamination of oil paintings in Japan 25
1982 to 1986. The paintings were executed by 39 Japanese artists and one French painter between 1890 and 1982. Most of these paintings had been kept in traditional Japanese houses without air conditioning.
Method of inspecting condition of oil paintings
The paintings were first observed visually under normal light and then under raking light to find areas of reduced varnish gloss. The paintings were next observed using a binocular microscope under magnifications of 7x:. 10x, 20X, and 40X.
Microbiological analysis
Samples of fungi were taken from the surface of paintings with a steriliized cotton swab. They were put on the surface of potato dextrose agar plate medium in Petri dishes of 90 mm diameter. Fungi were also collected in a storage room of the F. Company Collection. This was done by placing uncovered Petri dishes, with agar medium, in the storage room for 15 min.
The samples were incubated at 25-29°C for 7 days until colonies of growlLh were observed. Then a small amount of spores of each single colony of fungi were transferred aseptically to the surface of a new potato dextrose agar plate. This procedure was repeated until a pure culture of each fungi was obtained. Identification of isolated fungi was accomplished using,, the keys outlined by Gi lman (1957). Ainsworth (1965). Barnett (1972). and McGinnis (1982).
Preparation of paint samples for fungicide test
Ninety different colors ofoil paint, made by Matsuda Paint Co. Ltd, were used to prepare samples of two groups, A and B. The paint in A group was mixed in dishes with drops of poppy oil and the paint in B group mixed with drops of poppy oil containing 200 ppm Vinyzene (10,10'-oxy- bisphenoxy arsene; Ventron Corporation). Each color was painted using a flat brush in three rectangular areas of 1-5 X 4 .0cm arranged horizontally on a stretched pre-primed linen canvas of 22.7 X 15.8 cm. The paint samples were placed on a shelf in the office of the Art Conservation Laboratory in a vertical position where they were allowed to dry for 1 year before the varnish was applied. Infection by fungi was allowed to occur from the surrounding air during this time. The office was in a concrete building and was air condit ioned during the daytime in the rainy season.
26 Mavumi lnoue. Masako Kovano
Preparation of varnish containing fungicide
Vinyzene came dissolved in mineral spirits. Two different mixtures of Vinyzene-containing varnish were prepared: one containing 20 ppm and the other 200 ppm. Each preparation was achieved by dissolving the fungicide in 7% B-72 (methacrylate polymer: Rohm and Haas Co.) in toluene. The stock solution of Vinyzene is pale yellow, and it is clear when diluted in the varnish.
Application of Vinyzene-containing varnish to paint samples
After the l-year drying period, Vinyzene-containing varnish was applied to the surface of the test strips. One-third of the paint samples were sprayed with the 20 ppm Vinyzene-containing varnish mixture: one- third was sprayed with the 200ppm Vinyzene-containing varnish mixture; and the last third was sprayed with the 76 B-72 varnish without the fungicide.
Determination of the effects of fungicide on paints
The samples were inspected once a year after application of the varnish. starting in 1984. Several people inspected color changes with the naked eye. In addition, color change was also analyzed using a colormeter (Suga Test Instruments Co., Type SM-5-IS-2B).
Inoculation of fungi onto paint samples
Paint samples caught fungi in the room naturally while they were drying on the shelf in the office for 1 year.
RESULTS AND DISCUSSION
Deterioration of paintings by fungi
The controls exhibited foxing, or reddish-brown staining, on the linen support. The medium in the ground and the paint layers was decomposed n it became soluble in water. The paint samples became discolored and darker, while the gloss was reduced in the varnish and in the paint layers.
Fungal contamination of oil paintings in Japan
Identification of fungi
27
Three types of fungi develop on oil paintings. They are non-tonophilic fungi (a), those requiring the presence of free water: absolute tonophilic fungi (b). those that require dry conditions: and facultative tonophilic fungi (c), those that are in between the above two.
Most of the fungi found on the oil painting samples in this study were type (c). Oil paintings in areas of high humidity, on the other hand, are often subjected to attack by type (a) fungi. Absolute tonophilic fungi, type (b), are only found occasionally. Considerable numbers of bacteria also developed on the paint samples. Future research will investigate the bacteria. Fungi identified from 40 oil paintings are listed below (total number of samples collected -- 124). (See Table 1.)
Non-tonophUic fungi: Cladosporium sphaerospermum Cladosporium cladosporioides Trichoderma harzianum Tr~!choderma viride Ryizopus nigicans Filamentous fungi
Absolute tonophilic fungi: Aspergillus penicilloides
Facultative tonophilic fungi: Aspergillus niger Aspergillus glaucus Aspergillus versicolor Aspergillus flavus Aspergillus oryzae Ahernaria alternata Pencillium chrysogenum Penicillium frequentans Penicillium notatum Penicillium funiculosum Penicillium purpurgenum Penicillium sp. Fusarium moniliforme Fusarium sp. Saccharomyces sp. Ulocladium atrum
24/124 (19-4%) 20/124 (8-1%)
10/124 (8.1%)
3/124 (2-4%) 1/124 (0.8%)
1/124 (0-8%) 1/124 (0.8%)
57/124 (46.0%)
11/124 (8-9%)
5/124 (4.0%)
28/124 (22.5%)
4/124 (3.2%)
5/124 (4-0%) 1/124 (0-8%)
I'O
O
O
TA
BL
E !
Id
enti
fied
Fun
gi f
rom
Oil
Pai
ntin
gs i
n Ja
pan
Kin
d of
fung
i N
o. q
f pai
ntin
g~'
I 2
3 4
5 6
7 8
9 I0
11
12
13
14
15
16
17
18
19
20
a.
(I)
Cla
dosp
oriu
m s
phae
rosp
erm
um
• C
lado
spor
ium
cla
dosp
orio
ides
(2
) Tr
icho
derm
a ha
rzia
num
Tr
icho
derm
a vi
ride
(3
) R
hizo
pus
nigr
ican
s (4
) F
ilam
ento
us fi
mgi
b.
(5)
Asp
ergi
llus p
enk'
ilh'id
e~" s
pega
zzin
i
c.
Asp
ergi
lhts
ni
ger
• A
.weo
,,illu
s ghn
tcus
A
sper
gillu
s ve
rsh'
olor
A
sper
gillu
s fla
vus
Asp
ergi
llus
oryz
ae
(6)
(7)
(8)
(9)
(IO)
(il)
(1
2)
(13)
d.
(14)
(15)
(16)
Alt
emar
ia a
lter
nata
P
enic
illi
um c
hrys
ogen
um
Pen
icil
lium
freq
uent
ans
Pen
icil
lium
not
atum
P
enic
illi
um fu
nico
losu
m
Pen
icil
lium
pur
purg
enum
P
enic
illi
um s
p.
Fus
ariu
m m
onil
ifor
me
Fus
ariu
m s
p.
Sacc
haro
myc
es s
p.
Ulo
clad
ium
atr
um
Pre
use
Cep
halo
spor
ium
sp.
,4
ureo
basi
dium
pul
lula
ns
Pes
talo
tia a
dust
a
Bac
illu
s su
btil
is
Bac
illu
s sp
. P
rote
us v
ulga
ris
Pro
teus
sp.
Mic
roco
ccus
sp.
®
• •
• •
• •
• • ~"
(com
inue
dj
I,,J
TA
BL
E I
--co
ntd.
Kin
d of
fung
i N
o. o
fpai
ntin
gs
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
3,~
39
40
a.
( I )
Cla
dosp
oriu
nl s
phae
rosp
erm
um
Chu
lo.~
pori
unl c
lado
spor
ioid
es
(2)
Tric
hode
rma
harz
ianu
m
Tric
hode
rma
viri
de
(3)
Rhi
zopu
s ni
gric
ans
(4)
Fila
men
tous
fun
gi
b.
(5)
Asp
ergi
llus
penk
'ilh,
ith,s
spe
gazz
itti
c.
Asp
ergi
lhts
nig
er
Asp
ergi
lhts
gla
ucus
A
sper
gillu
s ve
rshv
lor
Asp
ergi
llu.~
'.lla
vus
Asp
ergi
llus
o~.'z
ae
(6)
AIt
erna
ria
aher
nata
• •
Q
e~
d.
(7)
Pen
icil
lium
ch~
. sog
cnum
P
e.ic
illi
um fr
eque
ntan
s P
enic
ilii
um n
otat
um
Pen
icil
lium
funi
colo
sum
P
enic
illi
um p
urpu
rgen
um
Pen
icil
lium
sp.
(8
) F
asar
ium
mon
il(f
orm
e F
usar
ium
sp.
(9
) Sa
ccha
n~m
w'e
s sp
. (1
0)
UIo
clad
ium
atr
um P
reus
e ( I
I)
Cep
halo
spor
ium
sp.
(1
2)
Aur
eoha
sidi
um p
ullu
lans
(1
3)
Pes
talo
tia a
dust
a
(14)
B
acil
lus
subt
ilis
B
acill
us s
p.
(15)
P
rote
us v
ulga
ris
Pro
teus
sp.
(1
6)
Mic
roco
ccus
sp.
2"
2"
32 Mayumi lnoue. Masako Kovano
Cephalosporium sp. A ureobasidium pullulans Pestalotia adjusta
Bacteria: Bacillus subtilis Bacillus sp. Proteus vulgaris Proteus sp. Micrococcus sp.
No growth:
1/124 (0-8%) 1/124 (0-8%) 1/124 (0-8%)
14/124 (11.2%)
6/124 (4-8%)
1/124 (0-8%)
21/124 (16.9%)
Effects of fungicide-containing paint
Table 2 shows the effects of fungicide mixed with oil medium. Mold growth was observed in only three patches of green in B group, the group that contained fungicide. On the other hand. molds grew in seven colors of the A group.
As shown in Table 3. mold growth was observed in 1-1% of the paints when varnish was applied. This percentage is 1/10 that of non-coated samples. These data indicate that varnish containing Vinyzene is effective in delaying the growth of fungi on oil paintings.
TABLE 2 Mold Growth on Paint Samples of A and B Groups
Color Number qf MoM Growth Color Tt:~ted
A Group B Group
White 3 Violet 6 Blue 9 Green 18 Yellow 17 Red 18 Brown 8 Black 3 Neutral tints 8 Total 90 Mold growth (%)
7 3 7-7 3.3
(Results after I year.)
Fungal contamination of oil paintings in Japan
TABLE 3 Effect of Varnish Containing Vinyzene
33
Color Number of Mold growth A group colors
No coating Varnish 20 ppm V. Varnish 200 ppm V.
White 3 0 0 0 Violet 6 2 0 0 Blue 9 3 1 I Green 18 I 0 0 Yellow 17 I 0 0 Red 18 I 0 0 Brown 8 I 0 0 Black 3 I 0 0 Neutral tints 8 0 0 0 Total 90 I 0 I I Mold growth (%) I I I. I 1.
Color 90 0 0 0 B group same as A Mold Lzrow~h (%) 0 0 0
(Examined 6.5 y e a ~ after coating.)
Effects of fungicide-containing varnish
The paint samples, on which fungicide-containing varnish had been applied in March 1983, were examined by three Japanese conservators in September 1989, after 6.5 years. There were no paint samples that changed color due to the Vinyzene-containing varnish. Some transparent crystalline deposit was found on the olive green of B group, and some pale yellowish oily deposit on the white lead of B group, as revealed by binocular microscopic inspection. Colormeter examination of the samples showed that a minor change had occurred in two violet colors (cobalt violet rose and supper violet), a blue color (French ultramarine blue), and in a white color (white lead). The color changes may be the result ofbrushmarks in the painted surface and not represent a real color change. The effects of fungicide on colors should be more thoroughly investigated in the future.
CONCLUSIONS
The deterioration ofoi l paintings by fungi is manifested in color change, decomposition of medium, and appearance of stains. These disasters are
34 Mavurni lnoue, Masako Koyano
fatal to the oil paintings, which consist of delicate color combinations. What is more, these are non-reversible changes, and fungal damage will progress as long as the fungi are active.
Facultative tonophilic fungi were predominant among the fungi growing on oil paintings in Japan. The next most common fungi are the non-tonophil ic fungi. Both require high levels of moisture to grow.
The Vinyzene-containing varnish was effective in suppressing the growth of facultative tonophilic, and non-tonophil ic fungi at both the 20 ppm and the 200 ppm levels. The Vinyzene fungicide did not affect the transparency of the varnish. However, 200 ppm Vinyzene, mixed with oil or varnish, may cause a minor color change to occur (three out of 180 cases examined). What needs to be further investigated is whether this change is derived from the fungicide, from the painting materials themselves, or from the sample preparation technique.
R E FE R E NC ES
Ainsworth, G. C. (1965). The FungL An Advanced TreatZw. Academic Press. New York.
Barnett. H. L. (1972). Illustrated Genera o[lmperfect Fungi. Burgess Publishing Company, New York. USA.
Giacobini, C., DeCicco. M. A., Tiglie, I. & Accardo. G. (1988). Actinomycetes and biodeterioation in the field of fine art. In Biodeterioration 7. ed. D. R. Houghton, R. N. Smith & H. O. W. Eggins. Elsevier Applied Science. London, pp. 418-23.
Gilman. J. C. (1957). A Manual of Soil Fungi. The Iowa State University Press, Iowa, USA.
Koyano, M. (1988). Fungal contamination of oil painting in Japan. Preprint. Seminar on Fungal Contamination for Cultural Property by Japan Institute of Insect Damage to Cultural Properties. 6 and 7 July. 1989.
McGinnis, M. R. (1982). Pictorial Handbook of Medically Important Fungi and Aerobic Actinomycetes. Praeger Press, New York, USA.
Salvadori. O. & Nugari. M. P. (1988). The effect of microbial growth on synthetic polymers used on works of art. In Biodeterioration 7, ed. D. R. Houghton. R. N. Smith & H. O. W. Eggins. Elsevier Applied Science. London, pp. 424-7.
DISCUSSION WITH REVIEWERS
Q. Is there any toxicity problem with Vinyzene? Is it only available in Japan?
A. Vinyzene (a commercial product of Ventron Corp., MA, USA) has low toxicity when mixed with plastic material, even though it
Fungal contamination of oil paintings in Japan 35
contains arsenic. Approximately 100 tons of it are produced ever)' year in Japan. The USA Environmental Protection Agency has approved the use of Vinyzene as a fungicide.
Q. Is Vinyzene UV-sensitive? Can you remove the Vinyzene-containing varnish without any ill effects on the painting?
A. Vinyzene is slightly UV-sensitive. The Vinyzene-containing varnish can be removed from the painting without any problem.
Q. Have you or will you t ~ any other fungicides? Would you recommend the use of this fungicide?
A. We have tried PCP and TBZ in the past, and will test others in the future if there are any that seem promising. Further investigation is necessary before we can confidently recommend the use of Vinyzene. However, indirect application of varnish containing the Vinyzene may be safe and effective in preventing fungal damage to paintings.
Q. Have you tested the utiliff of Vinyzene-containing varnish on egg tempera paintings?
A. We have not tested this yet.
