Controlled temperature, humidity and light do play a role in the safeguarding of our paper based cultural heritage in the sense that they slow dow3n the process of deterioration. Controlling temperature and relative humidity would help by retarding mechanical, biological and chemical deterioration.

As for mechanical deterioration, fluctuating temperatures and relative humidity would cause an expansion and contraction of the paper. In terms of biological deterioration, a high temperature and a high humidity would favour mould growth whereas in terms of chemical deterioration, a high temperature and a high relative humidity would favour self-decay and destruction of the paper.

Nevertheless, a control of the temperature and relative humidity and even light control are in no way a means to an end. As said by Strlic and Kolar (n.d), paper ?being a predominantly organic material, it will eventually degrade in even the most favourable conditions, though advanced conservation methods may be able to shift this event far into the future.?

No one knows the extent to which a controlled temperature, controlled humidity and controlled light would help. Tests have been carried out based upon accelerated ageing but it is not really the same as natural ageing in the natural environment. Maintaining a temperature of 20°C ± 2°C, a relative humidity of 40% to 60% and a constant light level of 55 to 165 Lux is not really feasible 24 hours a day and seven days a week.

It would be difficult to maintain tightly controlled temperature conditions, relative humidity and light intensities given that documents are even for use despite the fact that they should also be preserved. We cannot maintain such temperatures, relative humidity and light levels in reading rooms since it will be at the discomfort of users and paper is best preserved in the dark.

A slight fluctuation in temperature and relative humidity would be acceptable but repeated fluctuations would certainly cause some degree of damage to the paper. Taking out a document maintained at 18 °C to a heated reading room during the winter period would have a negative impact on the paper like the weakening of its fibres.

Controlled temperatures, relative humidity and light levels do help in prolonging the life of paper in the sense that we would avoid having mould growth, foxing (brown spots), paper brittleness etc. The method of maintaining temperatures, relative humidity and light levels at constant levels is not really feasible at times because books are here to be used by readers.

Other reasons like costs or that the library or archive is too old to install such systems which make that maintaining controlled environmental conditions are not always feasible. Thus, controlling temperatures, relative humidity and light levels do help to a certain extent but they are however not the answer to life long preservation.

<B>Deacification: does it help? What is ?deacidification?? </B>

Harris and Shahani (1994) see deacidification as the, ?processes that are used to extend the life of books, manuscripts and other paper based materials by neutralising acids in paper and impregnating it with an alkaline reserve that will continue to protect it from acid induced degradation in the future.?

Deacidification do have positive effects upon paper but it is not without the many side effects. There is as yet no ideal mass deacidification process and the already known ones, that is, Battelle, Bookkeeper, DEZ, FMC and Wei T?O processes all have side effects upon the paper. Some of the weaknesses of the different deacidification processes include the weakening of the paper itself, discolorations, staining, colour changes, Newton Rings, odour, bleeding of inks and any other morphological changes (Porck, 1996).

We can thus ask ourselves whether having recourse to deacidification would do more good than harm or even more harm than good. This question should be left to the respective libraries and archives since they are in a better position to assess their respective.

We cannot say that deacidification is a means to an end in terms of paper preservation. The reason being that the available mass deacidification processes carry with them various side effects that can in themselves damage the paper or have adverse side effects on the paper in the long run. However, it is true that deacidification processes do help towards the preservation of paper but does not entirely help us in permanently preserving paper.

<B> Fumigation: does it help? </B>

Fumigation includes the use of toxic chemicals in order to get rid of pests. It is ?the exposure of materials to water vapour of a volatile substance or toxic chemical in a closed container or chamber in order to destroy fungi and/or insects? (Smith 1996). It is believed that fumigation can do more harm than good since it has adverse effects on health and even upon the treated materials. As noted in Raphael (1994), ?fumigants are reactive chemicals that can produce chemical changes in object materials? and ?insect control procedures that use toxic chemicals or gases have been shown to present both short term and long term health hazards to staff who routinely handle or work near the materials.?

Commonly used fumigants such as ethylene oxide and thymol both have negative impacts on paper. As said by Peltz and Rossol (1983) in Parker (1988), ?ethylene oxide on cellulosic materials such as paper and textile changes the very nature of the material? and Parker (1988) further added the fact that ?some researchers have found that materials fumigated with ethylene oxide for mould control are actually more prone to mould attack and growth after the fumigation than before.? As far as thymol is concerned, it does more harm than good.

Firstly, it is a carcinogenic material and secondly, it causes the yellowing of paper and thirdly, ?while aging alone does appear to affect this paper slightly, exposure to thymol obviously accelerated the degradative process? (Isbell 1997).

There are of course other fumigants available such as methyl bromide, hydrogen sulphide etc but these are simply not acceptable for use with library materials (Parker 1988).

?Other reasons like costs or that the library or archive is too old to install such systems which make that maintaining controlled environmental conditions are not always feasible.?

(Part II)

<B>Tara Helena LAM</B>