BUILT HERITAGE SERIES: AN INTRODUCTION TO SIMPLE ANALYSIS METHODS FOR: EXAMINING SURFACE CONDITION (PART 1 OF 1)

BUILT HERITAGE SERIES: AN INTRODUCTION TO SIMPLE ANALYSIS METHODS FOR: EXAMINING SURFACE CONDITION (PART 1 OF 1)

BUILT HERITAGE SERIES: AN INTRODUCTION TO SIMPLE ANALYSIS METHODS FOR: EXAMINING SURFACE CONDITION (PART 1 OF 1)

Mrs. Emilia Zambri, MSoc Sci Tangible Heritage Conservation.

PREFACE

Welcome to this series of techniques for managing change and assessing the condition of architectural heritage structures and historic heritage fabric. This newsletter aims to provide professionals, including Heritage Consultants, Architects, Archaeologists, and Conservators, with practical and effective methods to determine the most appropriate approaches to management, conservation, and restoration.

Inspired by the challenges encountered in safeguarding historic heritage, especially in under-resourced areas, particularly in Africa, this series has been developed to assist colleagues globally. The goal is to present simple and easy-to-use frameworks, case studies, and tests that can be employed to evaluate the preservation, conservation, and restoration needs of historic heritage, ensuring their safeguarding for future generations.

By utilising these techniques, the objective is to empower heritage professionals with the knowledge and tools necessary to make informed decisions about the preservation of our shared cultural heritage. Join us as we embark on a journey to protect and preserve the historical structures that define our shared identity.

1. INTRODUCTION

Built heritage materials, such as structures and artifacts, are an essential part of our cultural heritage, and it is crucial to preserve them for future generations. However, over time, these materials may deteriorate due to various factors such as environmental factors, weathering, pollution, or biological growth. Therefore, it is essential to monitor and assess their condition regularly to ensure their preservation.

One of the most effective methods for examining the surface condition of built heritage materials is through the use of simple microscopy. This article aims to provide an in-depth analysis of the use of different types of microscopes for examining building materials, based on the works of Jorge Otero and A. Elena Charola. By examining the properties and benefits of various magnification instruments used, including the magnifying glass, digital microscope, stereo microscope, and Foldscope, this article seeks to provide a comprehensive understanding of their effectiveness for examining built heritage materials.

This articles ultimate goal is to provide valuable information for heritage consultants, archaeologists, and others involved in the preservation and conservation of cultural heritage materials. It is hoped that the information presented in this article will help facilitate better decision-making in the preservation of built heritage materials and contribute to the ongoing efforts to conserve our cultural heritage.

2. EXAMINING CONDITION

When examining the surface condition of built heritage materials, it is crucial to use the appropriate microscope with the correct magnification to identify the nature and extent of any deterioration. Depending on the material being viewed, different microscopes of varying magnifications may be necessary.

The most basic type of microscope is the magnifying glass, which can be used to magnify surface details smaller than 0.63 cm in the range of 3× to 25×. However, for building materials, the stereo and/or digital microscope would be more useful, as they allow for greater magnification ranges of 10× to 200×.

The stereoscopic microscope is considered the most relevant type of microscope in the field of conservation due to its ability to observe objects at higher magnification ranges while maintaining clarity and depth perception. Additionally, digital microscopes have been developed that offer similar magnification ranges and have the added benefit of being portable and able to record photos directly into a computer or smartphone.

Foldscope, a paper-based microscope, is an affordable and promising magnifying tool for built heritage materials. Its performance is comparable to that of more expensive microscopes, and its low cost makes it accessible to more people. Foldscopes are also portable, easy to use, and can be used to magnify specimens up to 140×.

Overall, selecting the appropriate microscope for examining the surface condition of built heritage materials is crucial to accurately identifying any deterioration and determining appropriate conservation measures.

3. TYPES OF MICROSCOPES AND THEIR USES

Microscopes are essential tools for examining built heritage materials and determining their surface condition. Table 1 provides a summary of the properties and benefits of different types of magnification instruments that can be used for this purpose.

The magnifying glass is a basic and inexpensive microscope that is portable and useful for identifying the nature of the material, surface cohesion, and deterioration patterns such as cracks, blistering, or crusts. It can also be used to identify biological growth or the presence of salts in the surface of the stone. However, its magnification range is limited, ranging from 3× to 25×, and it cannot provide high-resolution images.

Digital microscopes, on the other hand, offer a wider range of magnification powers and image quality, ranging from very inexpensive USB microscopes to advanced industrial digital microscopes. They are equipped with software for digital imaging processing, which distinguishes them from other types of digital microscopes. This makes them suitable for both field and laboratory work, and they can be used to capture and record images straight into a computer or smartphone.

Stereo microscopes are useful for observing the object at magnifications between 10× and 200×, making them ideal for examining building materials. They provide three-dimensional images of the object, making it easier to identify and study surface features. However, they are not portable and are often used in the laboratory.

Foldscopes are a promising type of microscope that are portable and low-cost, making them a suitable option for fieldwork. They provide a magnification power of 140× and are made of paper, making them lightweight and easy to carry. They are particularly useful for studying biological materials and offer high-resolution images.

In summary, different types of microscopes can be used to examine built heritage materials and determine their surface condition. The selection of the microscope will depend on the type of material being viewed, the desired magnification range, and the location of the examination.

4. METHODOLOGY

1. Preparation of the sample: The built heritage material to be examined will be cleaned and prepared for examination. Any loose debris or dust will be removed with a soft-bristled brush, and the sample will be placed on a stable surface.
2.  Selection of microscope: The appropriate microscope will be selected based on the nature of the material and the desired magnification range. A magnifying glass will be used for initial observations, with magnification ranges of 3× to 25×, to identify any surface details smaller than 0.63 cm (0.25 in.). A stereo microscope or a digital microscope will be used for more detailed examinations, depending on the specific needs of the study. Foldscopes may also be used, as they are portable and low cost.
3. Calibration: The microscope will be calibrated to ensure accurate measurements and observations. This will involve adjusting the focus and magnification settings, as well as any lighting or contrast settings.
4. Examination of the sample: The sample will be examined under the microscope, with particular attention paid to the surface condition and any signs of deterioration. The microscope will be adjusted as necessary to obtain the best possible image.
5. Documentation: The observations will be documented using photographs and notes, and any significant findings will be recorded. The photographs will be taken using either a digital camera or the built-in camera of the digital microscope, and they will be saved for later reference.
6. Analysis: The observations will be analyzed to determine the surface condition of the built heritage material. Any deterioration patterns, cracks, blistering, or biological growth will be identified and documented.
7. Recommendations: Based on the findings of the examination, recommendations will be made for the treatment and preservation of the built heritage material. These recommendations may include cleaning, consolidation, or protective coatings, depending on the specific needs of the material.

Overall, this methodology outlines a systematic approach to examining built heritage materials using different types of microscopes and documenting the findings for analysis and recommendations.

5. SAMPLING PROCEDURE

1. Define the population: Determine the population of built heritage materials that will be examined. This could include buildings, monuments, sculptures, and other historical artifacts made from various materials such as stone, brick, metal, or wood.
2. Identify the sampling frame: Create a list of all the built heritage materials in the population, which will serve as the sampling frame.
3. Determine the sample size: Decide on the desired sample size based on factors such as time, budget, and resources available. A larger sample size will provide a more representative sample of the population, but may not be feasible in terms of time and cost constraints.
4. Choose a sampling method: Decide on the appropriate sampling method based on the research question, population size, and available resources. Some potential sampling methods include simple random sampling, stratified sampling, or cluster sampling.
5. Conduct the sampling: Once the sampling method has been selected, randomly select the appropriate number of samples from the sampling frame. For example, if using simple random sampling with a sample size of 50, randomly select 50 built heritage materials from the sampling frame.
6. Examine the samples: Use the appropriate microscopes at different magnifications to examine the surface condition of the selected built heritage materials. Depending on the research question and sampling method, it may be necessary to examine the entire surface of each sample, or to focus on specific areas of interest.
7. Record and analyze data: Record observations of the surface condition of each sample, including any deterioration patterns, biological growth, or presence of salts. Analyze the data to identify any trends or patterns in the surface condition of the built heritage materials in the sample.
8. Draw conclusions: Use the findings from the sample to draw conclusions about the surface condition of the population of built heritage materials. It is important to note any limitations of the sampling method and any potential biases that may have influenced the results.

6. ETHICS

Firstly, the destruction of any portion of a historical monument or building should be avoided as much as possible. Therefore, samples should only be taken when it is absolutely necessary for understanding, conservation, or restoration. This means that the analyst should prioritize non-destructive methods of analysis before considering destructive methods.

Secondly, the analyst should be properly trained to ensure that they know what they are doing, and the sampling is done correctly to minimize the amount of damage to the original structure.

Lastly, before performing any destructive sampling, the analyst should obtain permission from the appropriate authorities and stakeholders, and ensure that the cultural significance and value of the heritage building or monument is fully taken into account. This includes conducting an ethical review of the proposed sampling procedure to ensure that it complies with relevant ethical guidelines and principles.

7. PERSONAL PROTECTIVE WEAR

Based on the information outlined above, there is no specific mention of protective wear required for examining built heritage materials. However, it is generally recommended that personnel involved in such activities wear appropriate personal protective equipment (PPE) to prevent exposure to potentially hazardous materials, such as lead-based paint, asbestos, or other toxic substances. This may include gloves, masks, respirators, safety glasses, and protective clothing.

In addition, when working with microscopes, it is important to ensure that the operator's eyes are protected from the intense light that may be emitted by the microscope, especially when using high magnification instruments. This may require the use of specialized eyewear or other protective measures.

It is also important to ensure that the work area is well-ventilated to prevent exposure to any fumes or particles that may be released during the examination. The work area should be kept clean and free of clutter to minimize the risk of accidents or injuries.

Overall, while there may not be specific mention of protective wear required for examining built heritage materials in the information outlined above, it is important to follow general safety guidelines and regulations to ensure the health and safety of personnel involved in such activities.

8. CONCLUSION

In conclusion, the preservation of built heritage materials is critical, and the use of microscopy techniques can aid in their examination and assessment. The various types of microscopes presented in this article offer different magnification powers and imaging capabilities, allowing for the identification of deterioration patterns, surface cohesion, and biological growth. These techniques are particularly useful for heritage professionals working in under-resourced areas worldwide, where resources for the protection of architectural heritage may be limited.

However, it is important to keep in mind that destructive sampling should only be done when absolutely necessary, and non-destructive methods of analysis should always be considered first. The techniques presented in this article offer simple and practical tests for assessing the conservation needs of architectural heritage, which can help preserve important historical structures.

This article provides valuable information for heritage consultants, archaeologists, and others involved in the preservation and conservation of cultural heritage materials. It is hoped that this information will contribute to the ongoing efforts to conserve our cultural heritage, ensuring that these important historical structures are preserved for future generations to appreciate and learn from.