## 3 EM Techniques for CH Diagnosis
### Infrared Spectroscopy (IRS) and Raman Spectroscopy in CH Applications
#### 3.7.2 Comparative Analysis of Techniques for Different CH Materials  
Effective preservation and assessment of CH materials--such as paintings, metals, ceramics, and paper--necessitate the use of specialized techniques tailored to each material's distinct properties. This subsection provides a comprehensive summary in Table 15, which compares the applicability of various analytical and conservation methods across different CH materials. By understanding the strengths and limitations of these approaches, conservators and researchers can make informed decisions to ensure the long-term preservation and integrity of diverse heritage objects [144]. Table 16 provides a detailed cost comparison to help CH institutions and researchers evaluate the feasibility of adopting THz technology relative to other electromagnetic methods. It offers valuable insights to facilitate informed decisions when incorporating THz systems into conservation and analytical processes. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline XRF & High (expensive equipment, specialized setup) \\ \hline FTIR & Moderate (more affordable, widely available) \\ \hline Raman Spectroscopy & Moderate to High (varies with setup complexity) \\ \hline SEM-EDS & High (costly instrumentation and maintenance) \\ \hline Infrared Reflectography & Moderate (cost-effective for imaging) \\ \hline X-ray Radiography & High (requires specialized radiography units) \\ \hline UV-Vis Fluorescence Imaging & Moderate (relatively affordable imaging systems) \\ \hline LIBS & Moderate to High (depends on the laser system) \\ \hline THz Systems & Low to Moderate (generally less expensive than high-end XRF, SEM-EDS, or X-ray radiography, but more costly than basic FTIR or UV-Vis systems) \\ \hline \end{tabular}
\end{table} 
Table 16: Cost comparison of THz vs. other EM methods to aid CH institutions in assessing adoption for conservation and analysis [93; 94; 95; 96; 97]. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Technique** & **Paintings** & **Metals** & **Ceramics** & **Paper** & **Notes** \\ \hline XRF (X-ray Fluorescence) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathbb{\Delta}\) & Non-destructive; caution on paper (possible radiation damage). \\ \hline FTIR (Infrared Spectroscopy) & \(\mathscr{S}\) & \(\mathbb{\Delta}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & Best for organic compounds; limited use on metals. \\ \hline Raman Spectroscopy & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & Excellent for pigments; use low-power laser on paper. \\ \hline SEM-EDS (Electron Microscopy + EDS) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathbb{\Delta}\) & Micro-destructive; minimal sampling required. \\ \hline Infrared Reflectography & \(\mathscr{S}\) & \(\bigstar\) & \(\bigstar\) & \(\mathbb{\Delta}\) & Mainly for paintings (canvas or wood panel). \\ \hline X-ray Radiography & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & Reveals internal structures. \\ \hline UV-Vis Fluorescence Imaging & \(\mathscr{S}\) & \(\mathbb{\Delta}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & Good for detecting retouching and restorations. \\ \hline LIBS (Laser-Induced Breakdown Spectroscopy) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathscr{S}\) & \(\mathbb{\Delta}\) & Slightly destructive; excellent for elemental analysis. \\ \hline \end{tabular}
\end{table} 
Table 15: Comparing the applicability of different techniques to various CH materials. Understanding the damage state or phase change of cultural materials is essential for their preservation and conservation. By analyzing inspection results--obtained through various non-destructive testing methods such as spectroscopy, imaging, or structural analysis--conservators and researchers can assess the integrity, stability, and deterioration processes affecting these materials.