Palm Leaf manuscripts of the world: material, technology and conservation
Anupam Sah
Abstract
This review deals with the expanse and depth of the literature in the field of palm leaf manuscript
conservation. It outlines the dispersion of the manuscripts, the history of their use and their present
availability. The material and technology of palm leaf manuscripts is then discussed, followed by
their degradation and a review of conservation practices. The paper concludes with an impression
of present practices.
Introduction
An important area of work of the Orissa Art Conservation Centre (OACC)1 is the conservation of
palm leaf manuscripts of the region and training in this field. Despite the fact that most of South and
Southeast Asia's wealth of knowledge had for centuries been written on palm leaves, development
of conservation ideas and practices in this sphere has been rather limited. Authoritative literature on
palm leaf conservation is scarce. It is hoped that this review will create a consciousness of the need
to publish and disseminate more studies in the field of palm leaf conservation. For the moment this
review strings together available literature to form a narrative touching upon various aspects of
palm leaf manuscripts.
There is a verse in the Panchatantra, a fourteenth-century compilation of stories by Vishnusharman
which runs thus,
Since verbal science has no final end,
since life is short, and obstacles impend,
let central facts be picked and firmly fixed,
as swans extract the milk with water mixed. [1]
In short, there is a need to distill the facts regarding palm leaf manuscripts, extracting the relevant
portions. It is hoped that the essential details are presented in this literature review.
Dispersion of palm leaf manuscripts
Palm leaf manuscripts, also referred to as palm leaf books [2], can today be found in collections
around the world. The size of collections ranges from a few manuscripts to tens of thousands of
bundles [3], with each bundle containing hundreds of folios. These manuscripts cover subjects as
diverse as astronomy, mathematics, medicine, music, literature, grammar, history, astrology and
scriptures. The primary reasons why these manuscripts find their way into collections are one, the
sheer value of the knowledge and information they contain [4] and two, the
Fig. 1 Some folios of the Ushaharana, an eighteenth century incised and illuminated palmyra palm
leaf manuscript (Orissa State Museum Collection).
exquisite illustrations and illuminations which accord the manuscripts the status of 'works of art'
(Figure 1).
Most collections are housed in museums and libraries, especially university libraries. An even
larger number of manuscripts are stored in monasteries, granthagars and community houses [5]. In
countries like India, millions of manuscripts are kept in homes where they are worshipped by family
members and household priests. Despite the fact that the manuscripts are sacred, hundreds if not
thousands are lost every year due to the cumulative effects of neglect.
The palm leaf manuscript
In Conservation of Manuscripts and Paintings of South-East Asia, Dr. O.P. Agrawal has covered
various topics relating to the palm leaf manuscript [5], the most common form of which is the
'bundle' comprising a number of folios of similar size, pressed between two wooden panels slightly
larger in size than the folios (Figure 2). Each folio is a flat leaf, up to 1 m in length and not more
than 8-10 cm in width, with a colour ranging from cream to a woody light brown. Alberuni, a tenthcentury historian, during his sojourn in India [6], records a processed palm
Fig. 2
Palm leaf folios bound between wooden boards, tied with a cord and wrapped in cloth.
1
OACC is a division of the Indian National Trust for Art and Cultural Heritage and the Indian
Council of Conservation Institutes (INTACH-ICCI).
leaf, evidently of the Corypha variety, measuring roughly 91 cm by 7 cm.
Folios have a hole bored in them through which a cord is passed to tie the bundle. At times these
bundles, as well as the leaves within, are shaped to resemble forms of fish, animals and daggers.
Some rare forms are also found, such as an Orissan manuscript in the shape of a garland [3] or an
Indonesian manuscript shaped as spools of tape [7].
History of use
It is difficult to say exactly when the palm leaf first began to be used for writing [5]. As palm leaves
are organic in nature and as susceptible to decay as any other natural material, scribes have been
recopying ageing manuscripts for centuries in order to sustain the transmission of their contents. In
the Indian subcontinent, after being copied the damaged manuscripts would be destroyed [3] usually
by immersion in rivers with due ritual and reverence. The practice of immersion is common even
today not just for manuscripts, but also for many objects like sculptures, puppets and paintings. To
the Indian mind, whether for humans or for manuscripts, the manuscript serves to pass down
knowledge, after which the gross form is returned to the elements. Bearing in mind that most extant
manuscripts are copies of earlier manuscripts which have since merged with the elements, it is
noteworthy that none of the surveyed literature touches upon the methodology, or indeed the need
to study and influence social practices in order to render a larger and deeper conservation
responsibility.
Perhaps the earliest known palm leaf manuscript is a fragment of the text of a second-century Indian
drama discovered in central Asia [5]. Other references [81 mention fragments from Kashgar, dated
to the fourth century AD (now in the Godfrey collection), a sixth-century manuscript written in the
Gupta script preserved in the Horyuji shrine in Japan and a seventh-century manuscript found in
Nepal. Manuscripts dated to the eleventh and twelfth centuries are found in Jaisalmer and Patan in
western India; the Cullavagga is the earliest extant palm leaf manuscript in Sri Lanka which is
dated to the thirteenth century AD [9]; and the spool-shaped manuscript of Indonesia, mentioned
earlier, is said to be seventeenth century. This is evidence not just of continuity in the creation and
use of palm leaf manuscripts over centuries, but also of the extent of their dispersion. Dating of
manuscripts, however, is difficult as often there is no mention of the author, the scribe or the year of
writing and when there is mention, the chronology and colophons are often erroneous [10].
Recourse then has to be made to the style of the text for dating the manuscript [7]. Dating of
manuscripts - as a subject in itself - as yet has not been explored.
Other than extant fragments and whole palm leaf manuscripts there are also historical references,
principal among these being the records of Hiuen Tsang (seventh century AD) and Alberuni (tenth
century AD) recording the practice of writing on palm leaves in India [6]. According to
Mahavamsa, the second-century Sri Lankan chronicle, Prince Uttiya, the brother of King
Kelanitissa, wrote a love message on a leaf to the Queen [9]. Another example lies in the earliest
layers of the Pali Buddhist canon from the fifth century BC which speak of various types of
material used for writing in India, among them being leaves [6]. By the sixth century AD, the art of
writing on palm leaves was well established in Orissa too as is seen in a copper plate inscription that
states that the text was first written on palm leaf and then transcribed onto the plate [3]. One of the
earliest depictions of a scribe incising palm leaves with a stylus has been sculpted in stone on the
seventh-century Parsuramesvara temple in Bhubaneswar.
Kesavan [6] mentions that paper was introduced into southern Asia around the eleventh century and
slowly over centuries it began to replace palm leaves, as well as other materials, as the principal
writing support. However, the practice of writing on palm leaves continued until the nineteenth
century after which it declined. By now there has been a complete change in the raison d'etre of the
palm leaf writing skills. From being the mainstay of education [11] and maintenance of records,
palm leaves are now reserved only for artistic, ornamental and ritualistic purposes [12].
Material and technology
Palm leaves
Manuscripts over the ages have been written on leaves from only a few varieties of palm trees, the
two most common being the Palmyra palm and the Talipot palm (Figure 3). The species of palm
trees and the preparation
Fig. 3 Leaves being cut from the Corypha umbraculifera Linn, also known as the Talipot palm or
the Fan palm.
of the leaves are topics covered in almost every publication on this subject. Clearly, there is a
tendency amongst many to repeat matter from a few source books and there is need and scope to
build on available information using field observation as a means to do so. Parameters like the soil
in which the palm tree grows, or the gender of the tree itself, could be of importance in determining
whether the leaves could have been used for writing.
Palm leaf is a generic term. In various regions where the use of palm leaves is alive, people also use
the vernacular terms which often imply a particular variety of leaf. In Sri Lanka the palm leaf is
known as Ola, in Thailand as Larn, in Burma as Lontar and in various parts of India as Tala, Sritala
or Karalika.
Composition of palm leaves
Plant anatomy and identification of plant material in artefacts has been discussed comprehensively
by Florian [13]. A comparison of the palm leaf varieties shows that some leaves are longer, wider
and thinner than others, but do they also differ in composition? How much do the Corypha Utan
leaf, Lontar [14] and the golden leaf, Bai Larn [5], from the Lopburi region of Thailand, differ in
composition to the other leaves? How similar or dissimilar are the leaf structures? Is it something
inherent in the Talipot palm leaf that makes it last longer than the Palmyra leaf? What role does
thickness play? Are the essential oils in the leaves different and does this have a bearing on the
suppleness and tolerance to insect attack as is often reported? These are areas that need to be
studied which in turn will lead to conservation solutions too.
Terminology
As students graduate to become young professionals, and perhaps eventually experts, too many take
for granted the numerous technical terms. In the process students sail past the fact that there are
more appropriate and accurate descriptive words. For example, a number of professionals [3, 4]
refer to the action of writing on palm leaves as 'etching', whereas the appropriate term is in fact
'incising'; and intervention by 'filling of holes' is more accurately expressed as the 'reinforcement of
a perforated folio' in the context of palm leaf conservation.
Preparation of leaves
The treatment of leaves in order to make them a suitable writing surface is usually referred to as
'seasoning' [14| but perhaps 'preparation of the writing support' or 'processing of the leaves' [5]
would be more appropriate terms. In different regions, palm leaves are prepared by a variety of
methods. In Sri Lanka, after tender leaves are selected and the midribs cut off [15], Ola leaves are
boiled, then interspersed with pineapple leaves before being washed, exposed to dew, fumigated
and burnished (Figure 4). They may be boiled with lime water too. In Thailand [5] they are heated
in kilns for 24 hours until a black exudation seeps out; the leaves are then wiped before being
heated and polished. In the Indian subcontinent they are boiled in water, buried under silt of ponds
for long periods and coated with spices and oils.
Fig. 4
Processed Talipot palm leaf strips.
But what are the reasons for the leaves to be subject to such treatment? As Kronkright states [13],
this may actually be the source of physical deterioration. Perhaps just boiling in plain water will do;
why in lime water and why with pineapple leaves? How does immersion in ponds help keep the leaf
insect free? Comparative studies would help to answer these questions.
Writing techniques
Throughout recorded history, palm leaves have been written upon in two ways. Text has been either
written on the surface of the prepared leaf or it has been incised in it. Today one can also see
screen-printed text and illustrations on palm leaves. Using single leaves has been the norm, though
from the twentieth century sometimes the leaves have also been stitched together in order to get a
bigger surface, which is especially useful for drawing large illustrations [12].
Traditionally, a palm leaf is held in one hand while the other is employed to write on it. Today one
can observe scribes who write holding the stylus in the manner of a pen while resting the leaf on a
rigid support such as a table (Figure 5). In a Sri Lankan traditional technique [15], a scribe would
cut a notch in one thumb nail to form a lever for the stylus to move on and writing was done
standing erect while swaying in gentle dancing movements [16]. Often called etching, perhaps
because as an onomatopoeia, it brings to mind the scratching sound made by the metal stylus
incising letters on the dry leaf. The basic character of the sharp metal stylus has not changed at least
in the past thirteen centuries.
The width of the leaf and size of the letters determines the number of lines of text on a folio. A
comparative examination of the various scripts in which palm leaves have been written reveals that
the scribes avoided incising horizontal lines. That could perhaps be one of the reasons why
manuscripts written in Devanagri script, which required horizontal strokes, were usually surface
written. When illustrations were drawn on the leaf, the text was truncated at the point where the
illustration panel began.
At this stage both the incised illustrations and text are barely visible [5]. In order to make them
legible, carbon black mixed with a binder is rubbed into the incisions and then wiped off with
water, rice bran or hot sand. The inking process itself needs to be studied in greater depth as
Fig. 5
A contemporary scribe incising text on a palm leaf using a metal stylus.
it often serves the additional purpose of making the leaf insect resistant. Common binders are gum
acacia or gingili oil in the Indian regions, wood oil in Thailand and Dudu or Dummela 'oil' in Sri
Lanka. Other than carbon black, red ink is often seen in Thai manuscripts as well as indigo 117],
vermilion and white. The juices of black thorn apple and bean leaves have also been employed to
render the text visible [18]. Perhaps a study of the inks could be used to help date manuscripts,
although there is a limiting factor in that manuscripts can be re-inked with ease at any time and with
a range of available materials.
Another method of placing text on the leaves is by surface writing (Figure 6), which has been done
especially on leaves of the Talipot variety. For surface writing, Palmyra leaves were rarely
employed, perhaps because they are
Fig. 6
A surface-written illustrated palm leaf from western India.
much darker. The Palmyra leaf also seems to be more waxy and hence less suitable to take on a
surface 'paint'.
Talwar [19] alludes to the Talipot leaf's ability to absorb ink and the inability of the Palmyra variety
to do so. In the preparation of ink, plant gums have been used as binders. The writing appears to
have been executed with chisel edged pens, often in black, although other colours were employed,
as in the lacquered Thai [20] and Burmese [5] manuscripts. One of the factors that distinguishes the
manuscripts of Thailand and Burma from those of other regions is the use of lacquers. Black
lacquers with gold illumination embellish the manuscript folios and sometimes red lacquer is
applied too. Amber lacquer is used on the Burmese manuscripts.
Illuminated palm leaf manuscripts
While most palm leaf manuscripts contain only text, many are illuminated with exquisite images
|3]. After inking was completed, illustrations were either incised or surface drawn and then gum
tempera paints were filled within the incised designs. There are allusions [3, 21] to the various
pigments used to illuminate palm leaf manuscripts, but these have not been substantiated with
analytical studies. This is another area that remains to be explored.
Palm leaf scribes
Very little is written about the people who wrote on palm leaves and the manner in which they
wrote. Scribes were obviously literate and either wrote their own manuscripts or were employed to
do so. While at times scribes could illustrate too, other times the scribe and illustrator were different
persons [10]. The caste system of the Indian subcontinent dictated who would pursue a certain
profession and there is evidence [10] of people who began to work on palm leaves even though they
belonged to other vocations. Although there are very few 'true' scribes left probably because there is
little demand for text on palm leaves, a number of palm leaf 'artists' still practice. Today scribes
cater to a ready market for illustrated manuscripts with popular images of deities, spiritual tales,
narratives of epics and coital positions.
In India, Burma, Laos, Thailand and Sri Lanka there remain a few pockets where the traditional
skills of preparing palm leaves and writing on them are still alive [22]. As the skills are dying out
there is need to list the various villages in the handful of countries where palm leaves were
traditionally made, thoroughly document the process and study traditional preservation techniques.
Cover boards
Once the leaves have been written or painted upon, they are bunched together and clamped tightly
between boards or panels, usually of wood. This assembly is either strung on a cord or kept in place
with bamboo plugs [2] that are inserted into holes bored in the leaves for this purpose. A cord is
wound tightly around the bundle to keep it in place. Often these boards were beautifully painted
from the outside, and at times were also embellished with mother-of-pearl or ivory inlay work.
Certain texts [11] contain formulae that denote where the cord holes should be made in the leaves as
well as the manner in which the cord must be wound around the manuscript.
Degradation and conservation
The majority of the palm leaf manuscripts date to the period between the eighteenth and early
twentieth centuries; those produced earlier than the eighteenth century are fewer in number
although these are not necessarily degraded. If palm leaves, especially those of the Talipot variety,
can survive as long as 600 years [23, p. 85], then degradation of these manuscripts seems to be
more a function of bad housekeeping than of time. This raises questions about the efficacy, or
absence, of conservation strategies and sensibilities. It might be asked if it would be better for
individuals to look after their own manuscripts with a personal touch and care. Institutions that have
collected thousands of manuscripts have a serious responsibility to ensure their upkeep [12].
Interestingly, none of the conservation literature surveyed deals with comprehensive practical
strategies to handle large collections of this material.
The steady deterioration and loss of manuscripts and the range of knowledge systems contained
within them is one of the reasons for efforts in various countries to document collections, often with
technical and financial assistance from European nations. The thrust rests on microfilming and
digitisation of the contents, rather than on the conservation of the manuscripts in their physical
form. Perhaps the reason for this is that if the text has been documented, and unless the manuscripts
are considered 'works of art' or historically important, then large resources should not be spent on
conserving the manuscripts, of which there are millions.
Insect attack
Insect attack is by far the most widely reported problem with palm leaf manuscripts (Figure 7) and
it has been observed that Palmyra leaves are more prone to it [5]. The insects identified are
Gastrallus indicus, termites, silverfish, bookworms and cockroaches. While insects migrate from
one infested collection to another, or from surrounding areas, at times the wooden cover boards
themselves could be the source of insect infestation 112]. The symptoms of insect attack on palm
leaves are the presence of neat, pinhead-sized holes, irregularly eaten edges, the presence
Fig. 7
Various factors of deterioration reduce manuscripts to such a state.
of larvae which eat the leafy matter forming channels in such a way that a paper thin surface
remains intact on one side of the folio [24].
There have been a number of traditional measures used to avoid insect attack. For instance,
manuscripts were often stored in kitchen lofts where smoke kept insects away; and the boards
between which the folios were stored were often made of a hardwood with insect resistant
properties, such as that of the Neem tree. In Thailand, to exclude subterranean termite attack,
important manuscripts have traditionally been housed in repositories known as Huw-tri [21]
constructed on stilts over bodies of water. In India, wrapping manuscripts in red or yellow cotton
cloth was a common practice that has come down to this day and current articles refer to use of red
and yellow coloured cloth wrappings to keep away insects [14]. However, whether the colour of the
cloth has any role to play in keeping away insects has never been substantiated in conservation
literature and research would be required to determine the attractive properties of colours for
insects.
Natural insect repellents
It has been common practice to keep a variety of insect repellent oils and herbs with the
manuscripts. The bark, leaves, seeds and wood of Margosa, the Neem tree (Azadirachta indica)
have been used in India for millennia for their medicinal and insecticidal properties which are
attributed to phenolic compounds and to the active ingredient azadirachtin. One report [25]
mentions that the slightly sticky greenish yellow oil - produced by pressing the Neem seeds - loses
its insecticidal and medicinal properties if refined. Most literature casually refers to the use of
Neem, having taken its efficacy for granted. In the reporting of an experiment in Dutta [25], at the
end it still remains unclear whether the insect free results were due to the oil or due to good house
keeping.
In Sri Lanka, from dummela, the fossilised resin of the Hal tree, a black liquid known as 'resin oil' is
distilled and used as an insect repellent. In Thailand, wood oil is used for the same purpose. A
number of oils like citronella, lemon grass, clove, sandalwood, black pepper, palmarosa, gingili,
dudu and artemisia [26J have been used in various regions.
The applications of many more natural biocides have been touched upon in the literature [5, 17]. A
combination of sweet flag, Acorns calamus, cumin, cloves, pepper, cinnamon, and camphor is
considered to be an effective insect repellent for a period of six months [14]. What role each
ingredient and their proportions play has not been defined, however. Similar is the case with
another observation in Wickramsinghe that mentions the use of dummela oil with a small quantity
of goraka maliang, a resin, and divullatu, a gum [9|. With the help of such profusion of seed
information, these indigenous herbs and oils of Asia could be thoroughly researched for their
application as insect repellents. Such research would contribute to the non-invasive methods of
protection for the millions of manuscripts in the world's collections. Studies like this could be
collaborative, involving entomologists, botanists, chemists and art conservators.
Synthetic insecticides
The introduction of modern chemical formulations for the upkeep of the subcontinent's collections
is expressed in a mid twentieth-century note in Bhattacharya [27], which states that in some
libraries, crude kerosene oil and liberal use of turpentine were employed to remove and prevent
worms and insects from boring holes into manuscripts. Naphthalene [5] too became popular and
still is favoured in manuscript collections and libraries. Over the years, para-dichlorobenzene
(C6H4C12, PDCB) has been used extensively as a fumigant, yet there are conflicting standards for
its use. Various dosages have been recommended:
•
•
•
•
1.5 kg per m3 for seven to eight days [8, p. 122]
PDCB at 65% RH [28, p. 77]
PDCB for at least ten days [29, p. 60]
fumigation with PDCB for 25 days [30]
The only point of agreement is that PDCB should be kept on the upper shelf as the fumes are
heavier than air. The use of carbon tetrachloride (CC14) is also recorded. Carbon tetrachloride and
trichloroethene (CHCl=CCl2) in equal proportion has been used as a fumigant [28, p.78]. In another
case [8, p.122) killoptera, a mixture of carbon tetrachloride (CC14) and ethylene dichloride, in a
ratio of 1:3 was employed, 225 ml per m3 for 24 to 26 hours, and the fumigation repeated after 21
days to eliminate larvae.
Health and safety
Other than the occasional reference to the smudging of carbonaceous inks, surprisingly there is no
mention of the deleterious effects of these chemicals on either the manuscripts or the users. Neither
toxicity, nor health and safety considerations have been touched upon. The indiscriminate use in
Asian collections of carbon disulphide (CS2), gammaxene and DDT - insecticides banned in most
countries - must be looked into and taken seriously. All of these chemicals are potentially hazardous
and yet are treated most casually in available literature relating to palm leaf conservation.
Loss of suppleness of the palm leaf
As a palm leaf manuscript folio ages, its suppleness or flexibility decreases and if bent beyond a
point, the leaves break. More pronounced with Palmyra leaves, this loss of flexibility is
accompanied with a progressive browning of the leaf. In contrast, the thinner and broader Corypha
leaves retain their pale creamish hue and their suppleness for much longer. Agrawal [5] and Nair
[31] attribute the loss of flexibility to the loss of essential oils and a breakdown of the leaf structure
which leads to brittleness.
To impart flexibility to the leaves, a common approach has been to apply oils of citronella, camphor
or lemon grass. The bit of flexibility imparted is temporary, however, and the oil on the surface of
the leaf attracts dust and may also cause the leaves to fuse with each other resulting in cleavage of
the epidermis layer if pulled apart carelessly [5]. Other efforts have been made to induce flexibility
in ageing palm leaves. In the past, glycerine or diethyl glycol [8] was brushed on leaves to render
them flexible but as the glycerine evaporated the leaves reverted to their brittle condition. An
attempt to apply a drying oil resulted in the oil hardening in the 'honeycomb' centre of the leaf, thus
rendering the leaf hard and inflexible [32]. The use of polyethylene glycol 200 (PEG 200) was
contemplated by Nair |31] but subsequent fungus attack was feared. Nair also suggested using palm
leaf extracts along with selected essential oils.
Palm leaves in dry climes are brittle while those in humid ones are relatively supple and, naturally,
this points to atmospheric moisture playing a significant role in the retention of flexibility. Oils
have never been applied at the OACC [33], instead taking advantage of the ambient relative
humidity of coastal India. For dry climes, the use of oil and water emulsion, coupled with
development of a system to retain the leaves' moisture content, has been suggested by Dr. Agrawal.
The author wonders if it is necessary to attempt to impart flexibility to the leaves at all. The
negative effects of such interventions can do much harm and the introduction of flexibility-inducing
agents in weakened plant material is fraught with negative effects with hardly any practical benefit
to the folio. The introduction of oils can create gradients between tissues causing structural damage
[13]; the introduction of water in the leaves causes swelling and shrinkage leading to failure of the
cell walls [13]; and PEG can solubilise lignin [13] once it begins to depolymerise. This concern is
echoed in the colophon of an Orissan manuscript wherein it is written that palm leaf manuscript
bundles should be kept tightly bound and must be protected from water and oil [18].
Microbiological attack
Dean [2] states that palm leaves are fairly resistant to fungus attack and it is not a rampant problem
in palm leaf manuscripts. However, fungus does occur as greenish black colonies [5] and other
varieties have been identified on Talipot palm leaves in the laboratory [34] where the penetration
studies indicate that it is not just the surface, but the whole leaf structure, that is affected in case of
fungus attack. Other than dust, an indirect source of fungus is the adhesives used in palm leaf
conservation. In a study by Rao et al. [30] that was conducted to observe the effect of the addition
of a fungicide to a synthetic adhesive, pentachlorophenol (C6C15OH) and dehydro-acetic acid were
added to a 10% solution of polyvinyl-acetate (PVAC) in toluene (C6H5CH3). Significant fungistatic
activity was noticed, an observation which implies that fungus growing on PVAC can be countered
by applying this fungicide in a definite concentration. In addition, perhaps some more fungicides
should be studied in relation to relevant adhesives. Adhesives used in palm leaf conservation are
carboxymethyl cellulose, methyl cellulose, acrylic emulsion adhesives, acrylic rubber, starch paste,
cellulose acetate, diluted paraffin wax emulsion and polyvinylacetate, as a non-aqueous solute and
as an emulsion. The tests may reveal the different varieties and relative growth of fungus on these
adhesives as well as the most effective types and concentrations of fungicides that should be added
to these adhesives before they are used for conservation.
To observe the fungicidal effects of various oils, Dhawan [34] conducted a study on Talipot leaves
affected by fungus. Screening of anti-fungal activity of selected oils on these leaves indicated that
betalvine, camphor and eucalyptus oils were effective while citronella and lemon grass oil had
limited effect. Even though this study was published in 1995, citronella and lemon grass oils are
still used most commonly today (perhaps because of their insect repellent properties).
Traditionally in Orissa, ostensibly to keep manuscripts free from fungus and also from insects,
manuscripts are shown the sun, especially during the month of August [18]. The post-monsoon air
and sun have been considered beneficial to the manuscripts; the reason for this needs to be
explored. If fungus does occur it can be removed from the surface with a swab and ethanol
(C2H5OH) [5] while fumigation with thymol vapours has been a common practice. Once again,
details of the quantity of the fumigant, effective fumigation time or hazards are treated incompletely
in available literature related to palm leaf conservation.
Cleaning
Because the leaves exhibit relatively little water absorbency, it has been suggested that incised
leaves be cleaned with distilled warm or cold water [5, p.41], applied with a cotton ball wrapped in
fine cloth to prevent the cotton fibres from 'catching' the irregular edges (Figure 8). Additives like a
non-ionic detergent, glycerine in water (1:10) or 0.2% sodium salts of ortho-phenylphenate
(COONa-O-OH) have been proposed [31]. Once done, the leaves can be rubbed dry with a cloth.
There is, however, the accompanying possibility of residues depositing in the leaf fibres.
For cleaning surface written or illuminated folios, an ethanol bath has been recommended, with the
addition of glycerine in equal proportion, as has been the use of 5% isopropanol (C3H7OH) and 1%
magnesium bicarbonate (Mg(HCO3)2) applied by swabbing or soaking. Suggestions like the use of
1,1,1-trichloroethane, followed by boiling with 5% camphor oil in alcohol [35], or the use
Fig. 8 Cleaning and imparting flexibility to palm leaves using oils, moisture and solvents carry
inherent risks.
of carbon tetrachloride (CC14), acetone (CH3COCH3) and benzene (C6H6), do not mention the
possible effects on the leaves after cleaning is completed. Other than further research, there is an
obvious need to be sensitive and conscious of the implications of conservation interventions.
Re-inking
When the binders in the inks weaken and pigment particles fall away, especially if the incisions are
shallow or when dye inks fade, the incised text becomes difficult to read. The term 'fading of ink' is
commonly used to refer to this loss of legibility of the incised writing. During re-inking, a process
discussed earlier, it would be worthwhile to use the particular gums, or plant juices, which also have
insecticidal and anti-fungal properties. As the inking process requires the ink solution to be applied
over the entire surface of the leaf, antibiotic properties would envelope the entire surface.
Inks have been consolidated with a 5% solution of cellulose acetate (CA) in acetone [8, p. 122] and
with a 5-10% solution of Bedacryl in benzene or acetone. One needs to weigh the risks and benefits
of introducing consolidants as compared to simply applying fresh ink. After all, is the purpose only
to render the incisions visible or is it also to preserve the 'original' ink particles?
Treatment of physical damage
The manual Save Palm Leaf Manuscript Heritage [12| outlines various types of damage and offers
simple preventive conservation solutions. Various forms and mechanisms of deterioration of
artefacts made from plant materials have been systematically outlined by Kronkright [13].
Some of the physical damage that a palm leaf folio may suffer due to environmental variations
includes cracks and cleavages which remain confined to the surface of the leaf |5|. Some have
observed cleavages to be more common with the Corypha leaf but no reasons are proffered [ 14]. A
study of the composition of the leaf structure could offer an answer. Surface cracks cause flaking of
the overlying paint layers [5]; flaking of paint layers is also attributed to the abrasion caused by the
frequent handling of the leaves and the fact that the surface of the leaves does not have enough
'tooth' for the paint layer to hold on to. Cleavage repairs can be done [5] with diluted
polyvinylacetate emulsion, preceded by ethanol and water to soften the leaf, fixing the cleavage
under light pressure. To fix flaking that may accompany surface cracks, a 2% solution of soluble
nylon is useful.
Tear repair and treatment of leaf edges
Due to the sessile venation of the palm leaf, tears develop horizontally more easily than vertically.
In fact, it is not possible to have a clean vertical tear on a palm leaf folio unless it is cut with a blade
[24]. Longitudinal and transverse cracks can be repaired using silk gauze, chiffon or tissue paper,
along with acrylic rubber adhesive, acrylic emulsion adhesive or starch paste. Edges of folios that
are brittle and perforated by insects are broken and lost, often due to careless flipping of the leaves.
Edges are also
Fig. 9
Tissue paper and methylcellulose gel are used to reinforce leaves perforated by insects.
Fig. 10 Reintegration of lost section of an illustrated palm leaf at the Orissa Art Conservation
Centre at Bhubaneswar.
damaged when the covers are smaller than the dimensions of the folios.
Traditionally in Thailand, lacquer is brushed on the leaf edges [5J. If the lacquer is too thick it may
harden the edge, and therefore perhaps plant gum could be considered as an alternative. In Sri
Lanka, a small flame is used to singe the frayed edges 115]. To protect edges and facilitate easy
handling, inlaying is also done using handmade paper [8].
Reinforcement of fragile leaves
Leaves perforated with tiny insect holes lose their mechanical strength, become fragile and need to
be reinforced. Mulberry tissue paper and methylcellulose (MC) are filled into the holes [5]. As a
variation to this technique [33] the holes are not filled full but just enough tissue and MC gel are
introduced to hold the leaf together while retaining its flexibility (Figure 9).
Leaf casting has also been suggested [8] but one problem has been overlooked: as mentioned
earlier, channels created by the larvae leave one surface of the palm leaf intact but very thin. For
leaf casting to be effective, the fluid should be able to pass through the hole and this is prevented by
the remaining thin surface. To compound matters, the paper-thin surface often has writing on it and
therefore its preservation is necessary.
Additional supports that are transparent, strong and flexible and silk gauze or chiffon with starch
paste have been used for particularly fragile leaves [5|. Tissue paper with 5-10% PVAC in benzene
has been suggested by Joshi [8] even though toluene would perhaps be a better option if PVAC is to
be used at all. To support a one-sided illustrated palm leaf design, fresh palm leaf has been used [5]
with PVAC emulsion and Nepalese tissue paper for better adhesion. The solvent lamination
technique, using tissue paper, cellulose acetate sheets and acetone, has also been employed but such
single-side lamination causes the folios to warp. In addition, transparency is not satisfactory owing
to the numerous air pockets that form between the tissue paper and the leaf's irregular surface and
incisions. Some of the solution may also be absorbed into the leaf, leaving deposits. Another
lamination technique practised in a few institutions is heat lamination (using pressure and heat at
60c-70° Celsius) 129, p.61].
This technique, however, is irreversible and is best V avoided.
Reintegration of lost areas
Due to constant movement, the cord that strings the folios together abrades and breaks the edges of
the cord holes. In addition, parts of the leaf may be lost due to insect attack or other physical
damage. To reintegrate the missing areas, pieces of hand made papers are fixed with PVAC
emulsion to the edges of the losses [5]. At the British Museum, another solution has been offered:
two layers of natural wood veneer, preferably birch, backed with paper and sandwiched with kozo-
shi paper using acrylic emulsion adhesive were cut to the shape of the lost area and fixed in place
|35, p.108].
A simple technique has been developed by this author [33] at the Orissa Art Conservation Centre
whereby processed palm leaves of similar thickness and hue are used to repair the missing area
(Figure 10). A variety of iron files are used to shape the intervention leaf and when the join is
'perfect', with the horizontal fibres of the leaf well aligned, the leaves are fixed using PVAC
emulsion.
Separation of fused folios
While some palm leaves may weakly stick together due to the presence of the oils that were applied
to impart flexibility, sometimes whole manuscripts are retrieved as solid blocks due to damage by
moisture, insects and neglect [17]. Three methods to separate fused folios are stated by Joshi [8|:
humidifiers and steam with the aid of a spatula effect the separation of fused folios; hot water and
glycerine are also used; and in the third method, hot liquid paraffin is reported to separate the leaves
that are then acetone washed, however, such leaves were found to become fragile. At the OACC it
has been observed that if stuck palm leaves are relieved of the pressure of the wooden boards and
left undisturbed, often after a month the leaves begin to separate on their own.
Warping, creases and other repairs
Palm leaves warp when they are stored without the pressure exerted by cover boards [12] and also
when exposed to uncontrolled drying in sunlight. To be flattened, such leaves have to be humidified
slowly and
then pressed between wooden covers. The same method can be employed to treat creases. An
Orissan palm leaf manuscript was found to have creases and folds by Talwar [19]. Such a leaf
would probably have been the thin and supple Talipot leaf, rather than a Palmyra leaf, which would
simply have broken if folded. This case is rare, if not improbable, however, as known Orissan
manuscripts have always been written on Palmyra leaves.
Other than the leaves, the lacquers, cover boards and paint layers often need treatment. In order to
treat chipped lacquer of Thai and Burmese manuscripts, it has been suggested [5] first to fix the
edges and then to fill in the lacuna either with pigmented lacquer or a mixture of kaolin and epoxy
resin. The wooden boards and paint layers are conserved in the manner appropriate for wood and
paint surfaces.
De-acidification
De-acidification of palm leaf manuscripts is a very uncommon treatment. Vapour phase deacidification has been attempted [8] with dilute ammonia fumes (1:10 ratio), placing the manuscript
on the bottom shelf of a chamber for four to five hours before exposing the leaves to fresh air for 10
to 12 hours. Aqueous de-acidification [19] has been tried with 0.15% calcium hydroxide (Ca(OH)2)
in water for 15 minutes followed by 0.15% solution of calcium bicarbonate (Ca(HCO3)2). No results
of these experiments have been tabulated, perhaps because de-acidification of palm leaves seems to
be an option rarely considered.
Conclusion
If this literature survey is any indication, art conservators-restorers especially in Asia must take on a
larger responsibility for conservation efforts. There is an urgent need to rethink strategies in terms
of the quality of conservation, documentation, dissemination of results as well as economics.
The volume of conservation work is enormous and it would be wise to carry conservation skills to
the grass roots, training people to be effective custodians of their own manuscripts [36]. To preserve
this vast heritage such simple practical steps must be taken. Steps should also be taken to tackle the
lack of awareness amongst policy makers and professionals - and eventually younger generations as
well - concerning the need to conserve manuscripts. Traditional artisans should be encouraged to
revive their palm leaf skills. There is a wealth of traditional, indigenous knowledge and resources,
and if tempered with contemporary knowledge and infrastructure, these can bring about a paradigm
shift in the way conservation problems of Asian collections are addressed.
It is time to turn over a new leaf.
Acknowledgements
The author acknowledges the guidance provided by Dr. O.P. Agrawal and the co-operation of
professionals and institutions - Gout of Orissa, NORAD (Norway), the Japan Foundation and the
Ford Foundation - who have
joined hands with INTACH ICI Orissa Art Conservation Centre to preserve Asia's cultural heritage.
Credit is due to the Orissa State Museum and Dr. Srinimal Lakdusinghe for the use of photographic
material. Acknowledgements are also due to the Editorial Board for providing this opportunity to
share thoughts. Noelle Streeton's comments and suggestions were instrumental in crystallising the
contents of this paper. Thank you, Sally Woodcock, for setting the ball rolling.
Glossary of terms
Corypha
Corypha umbraculifera linn, also known as
Talipot palm or Fan palm tree
Devanagari
the script in which Hindi, one of the Indian
languages, is written
Granthagara
a storehouse of manuscripts
Gingili
a seed from which oil is derived in India
Palmyra
Borassus flabellifer linn, the Palmyra palm tree
Talipot
see Corypha
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Author
Anupam Sah is the Director of the INTACH ICI Orissa Art Conservation Centre at Bhubaneswar.
His responsibilities include the execution of conservation and restoration interventions on varied art
materials, conducting training courses for Asian institutions, and development and implementation
of conservation strategies. During 1992-94 he specialised in the conservation of canvas and panel
paintings and polychrome wood sculpture at the Universita Internazionale Dell"Arte, in Florence,
took a mural painting conservation internship with ICCROM and studied 'Systems Thinking' at
Schumacher College in Totnes, Devon (UK). In 1993 he was awarded an MA in art conservation,
and a gold medal from the National Museum Institute, New Delhi. He has a BSc from the
University of Delhi and was born in 1968 and brought up in the Western Himalayas of India.