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An essential component of collection management is benchmarking a collection item's condition. This provides an opportunity to track the effects of the storage environment on the rate of deterioration of individual collection items and how the provision of access is affecting the physical condition.
Assessing the condition of film materials is a very labour and time intensive task. Due to the repetitive nature of film examination there are also ergonomic considerations in workplace design and task administration to ensure that staff do not suffer from Occupational Overuse Syndrome or other OH&S risks.
Equipment must be designed so that there is minimal static load placed on the neck and shoulders and adjustable for different peoples height etc. Chair height, distance between the winders and the amount of reaching people need to perform to fit and remove films from the winders are all considerations. Adequate space for ancillary tasks such handling film during recanning or notetaking is another consideration in workplace design as is temporary storage so that film cans are not causing trip hazards for other staff.
Task administration should be designed to reduce the amount of time that the dynamic loads are placed on arms and wrists. In designing the inspection job manual lifting also becomes a concern. Rostering the tasks and interleaving film examination with other duties are effective strategies to reduce the risk to staff.
To reduce eye strain adequate lighting is important. Not only is the amount of light on the work surface important but also the spectral quality of the light can assist in the examination. Diffuse sources (e.g. fluorescent) make it harder to pick minor scratching than more specular sources (e.g. small halogen luminaires). Luminaires with readily adjustable arms so that the lighting angles can be arranged for maximum efficiency will also make the task quicker and more accurate.
Transmitted light — such as a lightbox — can be a source of eyestrain. This is apparent when examining a film frame with a great deal of flare light from the surrounding lightbox. Flare light — equivalent to 'noise’ in a signal sense — reduces the eye’s ability to resolve fine detail. People often resort to squinting or otherwise straining their eyes to look for the condition details. Using appropriate masking of the lightbox or alternative methods of examining fine detail, such as quality magnifiers (poor ones introduce serious optical defects that can again cause eyestrain), can reduce the risk.
Until a film can or other form of enclosure is opened there is no accurate way of knowing the condition of the film, especially in respect to chemical deterioration and biological attack, such as mould. While decomposition gases and mould spores may present only a slight risk, the act of opening a can may cause the air inside the can to move towards the breathing zone of the staff member creating a high local concentration.
The workplace should include an area where the ventilation has been designed to remove air away from staff and the general workspace where film cans can be opened. If there is no other option then film cans can be opened cautiously out of doors.
If there is insufficient air movement and extraction in the workspace, decomposition gases and mould spores can build up in concentration. Eventually the situation may arise where staff become affected and contamination of other films can occur.
Any film handling process — be it by hand or through a machine — increases the risk of damage to the film. Poor film handling skills can result in direct physical damage to the film or create a situation where chemical deterioration is encouraged. All staff involved in film handling must be trained in correct handling procedures and regularly have their skills reviewed.
If the condition reporting is to be of any use in the future in assessing the success of the collection management procedures, then there must be consistency in the technique and the condition assessment at each inspection by all staff involved. These skills are easily lost if they are not regularly practised, as may be the case in small or infrequently attended collections. Clearly written documentation, preferably well illustrated, of the standards and work practices should be prepared and readily available for the staff to use.
A standardised condition report form has been developed by AV archivists from the South East Asia Pacific region and is in use by many regional archives. It has been devised to document the original condition of a film when it arrives at an archive but can also be used to track films already in a collection. This particular form was developed with the generally low resources available to AV archives in the South East Asia Pacific region in mind.
Physical damage to films, while of concern, tends not to get worse in storage. The long term factors that effect the usability of a film relate to biological factors and the base and image stability (if we include any magnetic film or magnetic striped film as image).
Long term storage is expensive. Maintaining suitable environmental conditions is at best a compromise between the desired life expectancy of the object and running costs. Included in running costs are both energy and net-letable-area (floorspace). Energy costs particularly are readily identifiable expenses with constant pressure to be reduced. However, maintaining a suitable storage environment is critical to prevent biological attack and chemical deterioration. Benchmarking the state of a collection is an important tool in being able to assess the success of any set of storage conditions or for providing evidence for the necessity in improved storage.
Surveying the collection to set the benchmarks is a major task but will provide a sound footing on which to measure the performance of decisions regarding the collection. While it is theoretically possible to measure or benchmark several factors in a single survey it is generally safer to concentrate on one or two factors.
Even if there have been no benchmarks established a survey can be used to determine the size of any major projects on the collection, e.g. planning resources for the duplication of severely deteriorating films.
To accurately determine the state of a collection, every object should be examined and reported. However, for most collections, this would prove to be an impossible task requiring resources far beyond those available. A statistical approach can be taken that samples the collection and from the smaller sample provides a clear picture of the state of the collection. The degree of confidence in results of this approach can be very high.
To determine the sample size required for the degree of confidence required the following formula can be used:
n = the size of the survey sample
p = the estimated number of “decomposing” films
E = error
z = standard deviations for the confidence level (for 95% z = 1.96)
q = p-1
N = the total number of films in population
Confidence level is the probability that the sample results are correct. 95 per cent is the usual degree of confidence in such tests. Confidence interval, also known as acceptable error, is the range that can be expected in the results.
For example, if a survey was carried out with a 95 per cent confidence level and a 3 per cent confidence interval and it was found there was a 10 per cent incidence of vinegar syndrome, this would mean that between 8.5 per cent and 11.5 per cent of the collection would be affected.
One of the greatest concerns for film collection managers around the world is the decomposition of the film base. Rapid decomposition is known to occur in all cellulose esters. The decomposition reaction by-products provide a ready clue to how far the reaction has proceeded. By measuring the acid levels around the film a fairly good picture of the degree of base deterioration that has occurred can be gained.
For cellulose nitrate films the test used to involve artificial aging and measuring the time taken to cause a colour change in an indicator test strip (Alizarin Red). This test is rarely used today as there are concerns over the accuracy of any artificial aging tests and the test was destructive requiring a small sample to be removed from the film at the head, middle and tail of the film. Currently there is no generally accepted non-destructive test for cellulose nitrate stability.
Cellulose triacetate, the overwhelming bulk of film collections, can be readily tested by several products. The Image Permanence Institute in Rochester NY, USA and Dancan in Denmark both produce test strips that reflect the acid content of the film under test. The test strips are strips of paper that have been saturated with a buffered indicator solution that changes colour around pH 4.5. Research has indicated that this pH corresponds to a free acid level of 0.5 a level considered to be the 'onset’ of deterioration.
The human vision system is good at comparative measurements in density and colour but is very poor at determining differences without a reference. Any benchmarking of image stability would require some standardised method of measuring changes in density and colour balance.
Moulds are readily controlled by controlling the storage environment, especially in respect to relative humidity. Below 60 per cent and moulds will cease to be viable. However, it is not always possible to maintain these conditions and the occasion may arise when the possibility of mould infestation in a collection needs to be surveyed. Moulds and the extent of the damage caused by their feeding and growth are readily seen by visual examination.
Temperature and relative humidity have been clearly identified as the major determinants in the rate of chemical deterioration of both film bases and images. Tools such as the Time Weighted Preservation Index are useful in predicting the potential life expectancy of film materials under changing conditions. However, to improve the accuracy of these predictions and to spot any potential problems in the air handling plant, regular monitoring of the environmental conditions inside each storage area is essential.
Long term collection of data can be used to plot energy usage on a seasonal basis and to identify improvements that can be made to the physical storage location to improve energy efficiency.
Another aspect to environmental monitoring is that of pollutants within the storage environment. Continual sampling and analysis of air is a very expensive option. However, since most air handling systems introduce less than ten per cent fresh air to reduce energy costs the levels of pollutants may build up to levels where, in the long term, they have an affect on the film. So examination of the effectiveness of any activated charcoal filters that are part of the air handling system is essential.
Any film handling project is very resource intensive. The most effective strategy for film preservation is controlled climate storage. Correct preparation prior to storage will improve the life expectancy of a film.
Projects to ensure all films are wound to the correct tension, cans are free from rust and there are no foreign materials, such as papers, stored in the cans could be considered maintenance. The goal is to ensure that films are properly prepared before being sent for long term storage.
Risk analysis or assessment projects form a vital part of cyclic maintenance.
Download: Condition report form