10.6092/issn.1973-9494/9237
Un gran numero di beni culturali sono vulnerabili ai parassiti poiché sono costi­tuiti da sostanze organiche. Tali beni possono essere deteriorati da diversi organismi viventi e spesso possono, loro stessi, essere un ambiente ideale per la crescita dei microrganismi. in particolare quando sono presenti condizioni climatiche favorevoli e assenza di luce.La modalità di conservazione dei manoscritti svolge un ruolo determinante per la loro tutela. Considerando il principio della priorità della conservazione rispetto al res­tauro, dovrebbero essere adottate diverse misure preventive, che porterebbero anche a una diminuzione dei costi di restauro.La Biblioteca centrale di Tabriz possiede una preziosa collezione composta da di­verse migliaia di volumi pregiati, documenti autentici e libri litografici. La biblioteca conserva il primo documento scritto in Iran: il “Vaghf Nameh Rab'-e Rashidi, Deed of Endowment of the Rab' i-Rashidi”. Il manoscritto di cui è autore Sheikh Rashid al-din Fazlollah è inserito nella lista del patrimonio dell’umanità UNESCO.
application/pdf
1973-9494
9237
en
Mozhgan Khalili Zonouz
Conservation Science in Cultural Heritage
preventive conservation
Identification and Control of Damaging Microorganisms in Manuscripts of Central Tabriz Library, Iran
Text.Serial.Journal
https://conservation-science.unibo.it/
18
Articles
2018-12-31
2019-03-18
2018-12-31
2019-11-05
239-255
CSCH
Mozhgan Khalili Zonouz
2018/12/31
10.6092/issn.1973-9494/9237
239
National Academy of Azerbaijan Sciences, Baku
1973-9494
preventive conservation
en
255
Identification and Control of Damaging Microorganisms in Manuscripts of Central Tabriz Library, Iran
https://conservation-science.unibo.it/article/download/9237/9072
18
I   DENTIFICATION AND CONTROL OF DAMAGING MICRO-
    ORGANISMS IN MANUSCRIPTS OF CENTRAL TABRIZ
    LIBRARY, IRAN

    Mozhgan Khalili Zonouz*13
    National Academy of Azerbaijan Sciences, Baku, Azerbaijan


    Keywords: hand-written, micro-organism, biological damage, preventive
    conservation


    1. Introduction

     Manuscripts are among the valuable heritage of any society, having recorded the
thoughts and science of their own era with the passage of time in order to transfer them
to later generations [1]. In their composition, the most eloquent script of the time was
used and skillfully fashioned with special designs such as illumination when all condi-
tions were met; important points to consider for this aspect were the subject, author,
calligraphy and size of the manuscripts.
     The efforts made by the author to prepare the paper and use the appropriate in-
struments to write are a separate topic. However, different scientific, historical, social,
cultural, etc. values are hidden in each manuscript. Since they have become a library-
based collection, they are regarded as valuable and outstanding heritage. The higher
the number of manuscripts in a library the greater the value of the collections housed
therein. Thus, when only one of the library books is known as world heritage and is




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
recorded in the world heritage list, it becomes and consequently represents the scien-
tific and cultural credit of that human society, bringing pride and growth for the country.
     Considering climate conditions, the mentioned copies and library collection are ex-
posed to biological, physical and chemical damage. In such cases, biological factors,
especially micro-organisms, are highly emphasized, since they use book materials as
nutrition and produce chemical effects.
     In order to identify the micro-organisms present in the Central Tabriz Library, which
is neither the first nor second place in the country in terms of number of books, while it
is ranked first in terms of its contents and universally-registered works, it is necessary
to consider this issue as a scientific research topic, and as a way of preparing conser-
vation methods to protect the materials against damaging micro-organisms. It can thus
be implemented as a fundamental science in manuscript archive centers.
     Based on the conducted analysis, attempts were made to utilize those scientific
capacities which were already available in Iran, based on library, field, and laboratory
studies in order to develop and adopt an appropriate plan of conservation science. In
this regard, the present study aimed to understand, analyze, and deduce from the col-
lected data and recorded findings and considering it a priority in amending the guide-
lines.


*    Corresponding author: Mozhgan.khalili@parasmoon.com

                                                                                              239
                                                                                        2. Methodology

                                                                                        The present study was conducted based on previous library, field, and laboratory
                                                                                     studies. The results of these studies were accordingly analyzed to extract the results,
                                                                                     leading to the formulation of necessary guidelines for the optimal conservation of the
                                                                                     valuable written works which will then be used at the Central Tabriz Library. Applying
                                                                                     and implementing the results arising from this study will also be useful in other libraries
                                                                                     and institutions.


                                                                                        3. The manuscript collection of Central Tabriz Library

                                                                                         The library contains 3265 manuscripts, as well as 5200 lithographic and movable
                                                                                     type documents. They are placed on shelves in a mobile shelving system where no
                                                                                     provision is made for the necessary air conditioning and climate control. In addition,
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                     some of the books are put in show cases for display purposes.
                                                                                         The manuscript collection in the Tabriz Central Library is one of the most important
                                                                                     in Iran. It has several thousands of manuscripts in its storage space and is of great
                                                                                     value because the majority of its books belong to the Ilkhanid period (1256-1394).
                                                                                     Furthermore, the “Vaghf Nameh Rab’-e Rashidi”, the Deed of Endowment of the Rab’
                                                                                     i-Rashidi, which is still in the hands of the Association of National Works, can be con-
                                                                                     sidered one of the most interesting and clearest examples of historical evidence of the
                                                                                     Ilkhanid Era and therefore a document of outstanding value.
                                                                                         The Gospel of the Apostles (Enjil Rasulan) is regarded as another fascinating work
                                                                                     in this collection, which has been carefully preserved for 1200 years and is kept in the
                                                                                     same showcase as the Endowment (Figure 1-2). Both of these beautiful works are
                                                                                     kept in the library and treated as precious gems. The gospel manuscript is a priceless
                                                                                     and outstanding volume and of great value in terms of contents. The gospel is written
                                                                                     in Assyrian (Syriac language) using an eastern Assyrian accent and letters.
                                                                                         Given the fact that this volume was written more than a thousand years ago on fish
                                                                                     skin and not paper, its value as a historical and cultural artifact, is unquestionable.
                                                                                         The books in Tabriz Central Library have been damaged due to frequent displace-
                                                                                     ments and no restoration steps have been taken to correctly preserve them [1] except
                                                                                     for some unprofessional repair work, as well as traditional and non-principled restora-
                                                                                     tion.
                                                                                         Climatic fluctuations are quite frequent in the library, in addition to physical, chemi-
                                                                                     cal, and biological factors, due to the evident damage in most books. In addition, ven-
                                                                                     tilation and air circulation in the enclosed space are stagnant and there is a lack of
                                                                                     standard shelving. The dust accumulated along the shelves (Figure 3-4) is therefore
                                                                                     an ideal hiding place for fungal spores and the growth of micro-organisms which to-
                                                                                     gether with the climatic fluctuations, all contribute to speeding up chemical, physical
                                                                                     and biological damage.




                                                                               240
Figure 1. Storage place of the “Deed of Endowment of Rab’-e Rashidi” and the “Gospel of the
Apostles (Enjil Rasulan)” manuscript




                                                                                                           CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 2. Storage place of a) “Endowment of Rab’-e Rashidi” and; b) “Gospel of the Apostles [Enjil
Rasulan]” manuscript.




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M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                     Figure 3. A sample of the book arrangement in the manuscript storage at Tabriz Central Library




                                                                                     Figure 4. A sample of the book arrangement in the manuscript storage of Tabriz Central Library




                                                                               242
   4. Climatic fluctuations during field studies
   Considering the widespread climatic fluctuations in the library the variations needed
to be recorded during the sampling since both factors of humidity and temperature are
related to each another and the slightest change in one can affect the other. In addition,
a lack of climatic recording means that there is no control over variations in environ-
mental conditions which leads to accelerating the deterioration of the works. Table 1
indicates the climate conditions recorded only during the sampling period.


Table 1. Climate conditions on the recorded days




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE


   5. Selection Method of the Studied Samples

   In order to identify the microorganisms in the central library, two methods were
selected.
   A selection of the samples with excellent value (Table 3).
   The “Vaghf Nameh Rab’-e Rashidi” is among one of the first written works in Iran
and registered in the UNESCO Cultural Heritage list.
   The “Enjil Rasulan” is the oldest book in the library; it is more than 1000 years old
and is written in Assyrian (Syriac) (Table 4).
   A random selection of 14 samples from the shelves with different titles (Table 5).




                                                                                             243
                                                                                        6. Methodology of fungus identification in Tabriz Central Library

                                                                                       The study is based on several processes as well as laboratory and library research.
                                                                                     The main steps are presented in the following seven points.
                                                                                       •   Sampling
                                                                                       •   Transporting the sample
                                                                                       •   Preparing the sample
                                                                                       •   Preparing the growth medium
                                                                                       •   Inseminating into the growth medium
                                                                                       •   Transferring to incubator environment
                                                                                       •   Analyzing the results daily for 4-6 weeks


                                                                                        7. Why do fungi and other microorganisms cause decay and decomposition
                                                                                        of paper objects?
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                         The significant ability of cellulose and collagen in the book structure allows moisture
                                                                                     to be absorbed through the atmosphere, which has relatively high humidity, enabling
                                                                                     the microbes inside a damp book to grow well and consequently affect the conditions
                                                                                     for its correct preservation and storage [2].
                                                                                         The relative humidity of libraries and warehouses for books and paper should be
                                                                                     kept constant if possible. Appropriate relative humidity and environmental temperature
                                                                                     should be 60% and 15°C (below 18°C, in general) respectively. If the humidity of a
                                                                                     library, in which the temperature is 15°C rises from 57% to 63%, each one thousand
                                                                                     tons of books can absorb about 10 tons of water vapor [3].
                                                                                         Some microorganisms are able to use the humidity which is released as a result
                                                                                     of cellulose decomposition, making decomposition of the cellulose by the fungus rise
                                                                                     to 0.55 gram of water for each gram of cellulose; this is the result of fungi feeding on
                                                                                     the cellulose itself. Storage and accumulation of water by a fungus colony makes any
                                                                                     other type of humidity unnecessary for its survival. As a result, fungus growth occurs
                                                                                     inside the book tissue. Humidity therefore plays a major role in the environment which
                                                                                     is necessary for fungus growth and survival has a secondary role.
                                                                                         Paper absorbs a large amount of humidity and has non-uniform hairy characteris-
                                                                                     tics. Based on the type and method of producing the fibers in the paper, the quantity
                                                                                     and quality of the glues and filling materials, the type and method of production and
                                                                                     dehydration, the manner of covering the books and storage, and the temperature and
                                                                                     humidity contents of the actual paper, the materials show a varying degree of sensitiv-
                                                                                     ity or resistance against attacks from micro-organisms [4]. Fungi prefer acidic environ-
                                                                                     ments for their growth and bacteria, a neutral or slightly alkali one. Cellulosic (cellulose
                                                                                     decomposing) fungi, bacteria and actinomycetes grow well in paper, in an acidic pH
                                                                                     equal to 4 or less, a pH of 6.8-8, and a pH of 5-8, respectively.
                                                                                         Also temperature and relative humidity influence fungi growth. For example, in dry
                                                                                     air and dehydration, and cold air, fungi growth stops. The most appropriate conditions
                                                                                     for growth are temperatures between 24-30°C and humidity/RH of 65% - 80%. Most
                                                                                     bacteria can grow in anaerobic conditions; however, all fungi need oxygen for their
                                                                                     growth, even though some fungal spores are able to tolerate low-oxygen conditions
                                                                                     for a short time.
                                                                                         The spores of Penicillum and Aspergillus fungi can tolerate low-oxygen conditions


                                                                               244
at least for two weeks, while Rhizopus, Cladosporium, and Alternaria spores lose
strength in such conditions. Due to the range of the nutritional spectrum of the fungi,
fungal spores are present everywhere, making environmental control a very essential
and determining issue. It is generally recommended that library-based materials be
kept in conditions of relative humidity between 50% - 55% at a temperature between
16-18°C and suitable ventilation.
     More than 350 different fungal species attack books and paper objects, causing
some decay and destruction, among which 20 species can also cause fungal and al-
lergic diseases in human beings.
     Fungal attack on the book starch and glue leads to their decay. After digesting the
starch, the mold attacks celluloid tissues and subsequently rots the paper. However,
it is easy to distinguish the rotting impact of the acid and the mold from one another.
     Acid renders the paper crisp and fragile, thus the paper, which generally becomes limp
after fungal attack, cracks when it is folded while maintaining its soft flexible state. This
is due to the moisture content in the paper which keeps the texture of the paper flexible.
     In addition, molds alter the paper’s ink and iron composition causing the writing to
gradually fade away. This makes the manuscripts illegible, destroying their original
value once the chemical reaction is complete.


   8. Paper classification

   Paper can be classified based on its resistance to fungi, its resistance depending on
the chemical operations employed in the stages of its production.
   Machine-made paper from wood paste is more vulnerable than hand-made paper,
which is mainly composed of cloth pieces.
   Starched paper shows higher resistance against fungi as they absorb less humidity.
   Paper, whose pH is from 5.5 - 6 is resistant to molds.




                                                                                                       CONSERVATION SCIENCE IN CULTURAL HERITAGE
   Paper polished with a machine is less resistant against mold due to its softness,
cleanness, and humidity-absorption.
   Thicker sheets of paper absorb fungal spores. Paper sheets containing gelatin
starch or starch by itself, encourage mold growth [5].
   Decay, which occurs through biological factors in paper as well as other related fac-
tors, is called “biological decay or spoiling”. In books, apart from paper, other materials
have also been used such as paperboard, leather, cloth, glue or resin, all of which are
potential food sources for micro-organisms.
   Some papers are made of wood while others are made from cotton and waste pa-
per. However, paper is composed of celluloid materials and the most common factors
for the biological decay of paper are bacteria, insects, and fungi, of which bacteria are
the least important.
   Fungal biodeterioration is considered to be the main threat for paper documents in
archives and libraries, since they are apt to decompose celluloid materials. The pres-
ence of fungi is visible as spots on the paper, pus or filthiness, with evident signs of
decay and frailty [6].
   The impact of the fungi is visible as spots of different sizes with irregular round
shapes in black, red, purple, brown, yellow, green and without color. The colored spots
on different surfaces of natural (plant leaves) or artificial (paintings, paper, etc.) materi-
als are called “mildive plant rust”.


                                                                                                 245
                                                                                        Such variations in the color of the spots, as well as their brightness or darkness, de-
                                                                                     pend on various factors such as the composition of the paper, acidity, and the assault-
                                                                                     ing fungus species, along with the simultaneous presence of other micro-organisms
                                                                                     and the duration of their growth [7].
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                                                      Figure 5. A mold-corrupted book

                                                                                        9. Laboratory findings and field-based studies

                                                                                        According to the statistical results given in Table 2, based on field and laboratory
                                                                                     assessments, it can be said that 100% of lithographic manuscripts in storage are cor-
                                                                                     rupted with micro-organisms.

                                                                                     Table 2. Results of field and laboratory studies

                                                                                         Fungus species         Number of experimented plates Percentage of growth results

                                                                                        Aspergillus niger                        26                          35.5

                                                                                        Aspergillus rhizo-
                                                                                                                                  8                          10.9
                                                                                              pus

                                                                                       Aspergillus flavus                         1                          1.3

                                                                                          Cladosporium                            1                          1.3

                                                                                           Catheomia                              1                          1.3

                                                                                           Penicillium                           25                          34.2

                                                                                          Sum of grown
                                                                                                                                 73
                                                                                             plates




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Table 3. Selected sample of Rab’-e Rashidi




                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE




                                             247
      M. Zonouz - Identification and control of damaging microorganisms in manuscripts




248
                                                                                         Table 4. Selective sample of Enjil rasulan
Table 5. Randomly-selected sample Khazan and Bahar




                                                           CONSERVATION SCIENCE IN CULTURAL HERITAGE




                                                     249
                                                                                     Table 6. Biological damage in cultivated samples
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                        10. Presenting control solutions

                                                                                         According to the scientific association of CCI, the easiest, safest and most effective
                                                                                     methods of preventing and controlling the fungi and currently-used methods are non-
                                                                                     chemical methods [8]. They are employed for organic substances in museums and
                                                                                     library collections. Non-chemical methods include prevention, non-chemical control,
                                                                                     and taking safety measures when working with affected works. Suitable preventive
                                                                                     conservation can stop the growth of microorganisms and preserve the condition of the
                                                                                     written works.
                                                                                         Correctness, safety and practicality are the principle technical characteristics to
                                                                                     take into account in archive storage, as well as the rooms containing the documents
                                                                                     and objects. These three aspects are connected to each other and should therefore be
                                                                                     examined as a whole and not separately.



                                                                               250
  11. Location of the archive

  Whatever the type and design of the building, the areas mentioned below should
never be used for storing archives:
  •    Unsafe environments, such as damp cellars and attics which get very warm in
       the summer and very cold in the winter.
  •    Dangerous environments – in proximity to steam tanks, boilers, etc.
  •    Problematic environments in terms of accessibility (remoteness from the city,
       bad roads, etc.)
  •    Objects and documents should not be placed in places without control or sur-
       veillance or where they are easily accessible to any person.
  •    In the case of archive rooms being separate from other parts of the main build-
       ing with walls, doors or fireproof floors, the objects and documents should be
       transferred using trolleys and automatic belts.


  12. Shelving

   Preventive conservation is an appropriate solution to impede or arrest the prolifera-
tion of micro-organisms and maintain the originality/integrity of written works in col-
lections and libraries. First, both the environment and the books should undergo a
cleaning phase, as well as disinfection (asepsis) and all sources of dust accumulation
should be eliminated. Pollutants also need to be identified and removed because they
affect the artifacts and manuscripts stored on the shelves and will eventually lead to
their deterioration. All manuscripts should be transferred to the archives for correct
storage on specifically designed standard shelves. The storage system should also
include climate control and appropriate covering and shelving materials.




                                                                                                 CONSERVATION SCIENCE IN CULTURAL HERITAGE
  13. Shelf storage

   Shelves are the main structures used for storing materials in archives. Their sizes
are more or less standard and installation methods are the same in most countries [9].
   As shown in Figure 3 a shelf may be mobile or stable. Thus, the following issues
should be considered during their selection.
   In order to prevent fungus and mold growth, there should be the possibility of air
exchange and circulation between the shelf and its surrounding environment, which is
done according to precise calculations.
   Shelves are preferably made of metal due to the problem of common pests in wood
and paper.
   In order to avoid any chemical impact, it is necessary to use an appropriate cover-
ing. The use of zinc-plated materials with their high-quality powder coating improves
the surface and adds to the protection against aggressive substances in the archival
items, as well as a providing shelving. The shelving is constructed based on the books’
volume, shape and statics.
   Nowadays, steel plate is usually the material used for making archive shelves for
collections and libraries. Wood was used for shelving for a long time, but today the use



                                                                                           251
                                                                                     of wood is no longer very common, due to its easy combustion and the danger posed
                                                                                     by termites as well as other insects.




                                                                                     Figure 6. Samples of stable and appropriate shelving for the archive of books and written works
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                        14. Acid-free boxes

                                                                                       Generally, acid-free boxes are made of acid-free paperboard which means they are
                                                                                     made of paper that has a pH that is neutral or alkaline. 100% bleached cellulose has a
                                                                                     pH of 7.5 -10 which is known to be acid free. Such packaging plays an important role,
                                                                                     especially for written works, documents, and vulnerable materials.
                                                                                       As shown in Figure 7, these boxes provide suitable conditions for storing docu-
                                                                                     ments and books due to their paperboard structure.




                                                                                                                Figure 7. Acid-free boxes and packaging

                                                                                        Firstly, they prevent dust accumulation on the surface of manuscripts, breaking any
                                                                                     direct connection and consequently, interaction of physical pollutants with the books.
                                                                                     Secondly, they resist chemical factors, minimizing the possibility of chemical damage
                                                                                     from air pollutants.




                                                                               252
  15. Desirable climate conditions: relative humidity and temperature measure-
  ment

   Based on the above-mentioned issues, the temperature and humidity where the
collections are kept should be frequently measured so that they do not exceed the
desired limit. This rule is applied to all geographical areas and all building types. The
thermometer should be installed in the building accurately and the temperature should
be recorded in various places at different times, since warm and cold air circulate in-
side the environment according to their lightness and heaviness.
   A thermo-hygrometer is a device which measures environmental humidity. The sling
thermo-hygrometer is considered the simplest type while the mechanical variety is the
most complicated one. As illustrated in Figure 8, an appropriate thermo-hygrograph
and thermo-hygrometer can be used to measure the humidity and temperature of the
inner pages of the books, simultaneously.




                                                                                                  CONSERVATION SCIENCE IN CULTURAL HERITAGE



                              Figure 8. Thermo-hygrometer




                                                                                            253
                                                                                           a 					                                          b
M. Zonouz - Identification and control of damaging microorganisms in manuscripts




                                                                                     Figure 9. Equipment for mapping temperature and humidity; a) thermo-hygrometer with a probe
                                                                                     can be connected to shelves and display cases; b) data-logger to record and archive temperature
                                                                                     and humidity changes in the archive.



                                                                                           References

                                                                                     [1]     Fadayi, Gh. (2007). Acquaintance with Manuscripts and Rare (Persian and Ara-
                                                                                             bic) Works, 1st edition, Tehran, SAMT Publications.
                                                                                     [2]     Beniger, D. (2007). Insect Pests in Museums, trans. Farahmand Boroujani, Gol-
                                                                                             dasteh Publication, 1st edition.
                                                                                     [3]      Qahri, M. (2006), A Review of Harmful Fungal Factors of Paper, Pathology and
                                                                                             Preventive and Confrontation Methods, Restoration and Research Journal, Year
                                                                                             1, No. 1.
                                                                                     [4]     Dawson, J.E., revised by Strang, T.J.K.,) 2000(. Solving Museum Insect Prob-
                                                                                             lems: Chemical Control in Technical Bulletin N.15, Canadian Conservation Insti-
                                                                                             tute, ISBN 0-662-28311-2, Canada.
                                                                                     [5]     Guilds & MacDonald, M., (2004, Mould Prevention and Collection Recovery:
                                                                                             Guidelines for Heritage Collections.
                                                                                     [6]     Evans, E. J. and Richardson, M. D. (2003), Mycology (Practical Methods), trans.
                                                                                             Alireza Khosravi, 2nd edition, Academic Center for Education, Culture and Re-
                                                                                             search (Tehran Branch).
                                                                                     [7]     Strang, J.K.T. and Dawson, J. E., (1991). Controlling Museum Fungal Problems
                                                                                             in Technical Bulletin N.12, Canadian Conservation Institute, ISBN 0-662-54950-
                                                                                             3, Canada.
                                                                                     [8]     Niknam, M. (1992), Pests and Damages of Library Materials, Secretariat of
                                                                                             Board of Trustees of General Libraries of the Country.
                                                                                     [9]     Zanooz, K. H., (2006). Storage and Archive Solution, Parasmoon Publication




                                                                               254
  Biographical notes

   Mozghan Khalili Zonouz is a PHD candidate at Azerbaijan National Academy of
Sciences. She is also a lecturer in the IAU south branch of Tehran. She has presented
a number of articles in international conferences on restoration as well as at the 2nd
international conference in Tbilisi, Georgia, on International Biodeterioration & Bio-
degradation in Tehran. She has also carried out research projects in historical books,
documents and methods relating to conservation. She has experience in the conserva-
tion and restoration work of artifacts and books in Golestan Palace and Malek Museum
and Library.

   Summary
   A large number of historical artifacts have low resistance to pests since they are
made of organic substances. Such works can be consumed by several living organ-
isms and can often be an ideal environment for micro-organisms to grow, particularly
when favorable conditions such as appropriate climate and absence of light are pres-
ent.
   The way in which manuscripts are stored in archives, such as shelves, acid-free
boxes and relative temperature control, means that both humidity and aerosols can
play a determining role in their safety. Considering the principle of the priority of con-
servation over restoration, several measures should be adopted for the safety and
authenticity of the works, which will also lead to a decrease in restoration costs.
   The Central Tabriz Library possesses a precious collection consisting of several
thousand volumes of valuable books, authentic documents and lithographic books. It is
worth noting that the first hand-written work from Iran to be registered on the UNESCO
Memory of the World Heritage list was, “Vaghf Nameh Rab’-e Rashidi”, the Deed of En-
dowment of the Rab’ i-Rashidi. The document is a historical manuscript book authored
by Sheikh Rashid al-din Fazlollah and is regarded as a part of this collection.




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
    Riassunto
    Un gran numero di beni culturali sono vulnerabili ai parassiti poiché sono costi-
tuiti da sostanze organiche. Tali beni possono essere deteriorati da diversi organismi
viventi e spesso possono, loro stessi, essere un ambiente ideale per la crescita dei
microrganismi. in particolare quando sono presenti condizioni climatiche favorevoli e
assenza di luce.
    La modalità di conservazione dei manoscritti svolge un ruolo determinante per la
loro tutela. Considerando il principio della priorità della conservazione rispetto al res-
tauro, dovrebbero essere adottate diverse misure preventive, che porterebbero anche
a una diminuzione dei costi di restauro.
    La Biblioteca centrale di Tabriz possiede una preziosa collezione composta da di-
verse migliaia di volumi pregiati, documenti autentici e libri litografici. La biblioteca
conserva il primo documento scritto in Iran: il “Vaghf Nameh Rab’-e Rashidi, Deed of
Endowment of the Rab ‘i-Rashidi”. Il manoscritto di cui è autore Sheikh Rashid al-din
Fazlollah è inserito nella lista del patrimonio dell’umanità UNESCO.




                                                                                             255
