Analysis of Decorative Paintings in the Dragon and Tiger Hall of Yuzhen Palace: Culture, Materials, and Technology

Abstract

Yuzhen Palace in Wudang Mountain, established in the 10th year of the Yongle reign of the Ming dynasty (1412 AD), is a significant heritage site within the ancient architectural complex of Wudang Mountain, recognized as a UNESCO World Heritage Site. Despite being entirely relocated, the original paintings on the wooden beams of the Dragon and Tiger Hall exhibit clear characteristics of early Ming dynasty style, potentially being the only surviving wooden painted structures from the Ming dynasty in Wudang Mountain. To protect these valuable cultural relics and provide accurate information regarding the construction period of the paintings, this study sampled the paintings from the central and western sections of the front eaves in the Dragon and Tiger Hall. Using optical microscopy, scanning electron microscopy (SEM), Raman spectroscopy, and infrared spectroscopy, the study analyzed the stylistic features, material composition, and craftsmanship of the paintings. The results indicate that the paintings are typical official Xuanzi paintings from the early Ming dynasty, consistent with the style of the Golden Roof in Taihe Palace, Wudang Mountain. The pigments used are all natural minerals: azurite (2CuCO₃·Cu(OH)₂) for blue, malachite (CuCO₃·Cu(OH)₂) for green, and vermilion (HgS) and hematite (Fe₂O₃) for red, reflecting typical early Ming dynasty characteristics. The craftsmanship shows that the paintings were applied directly onto the wooden components without a ground layer, using ink lines to outline the images, and a thin ground layer made of tung oil mixed with lime was applied under the oil coating. This study provides scientific material analysis and data support for the subsequent protection and restoration of the Yuzhen Palace architectural complex, ensuring the preservation of these historically and artistically significant relics for future generations.

1. Introduction

Yuzhen Palace, situated on Wudang Mountain, was established in the 10th year of the Yongle reign of the Ming dynasty (1412 AD). It is a significant heritage site within the ancient architectural complex of Wudang Mountain, recognized as a UNESCO World Heritage Site (as shown in Figure 1). The palace was constructed under the decree of Emperor Yongle, who sought to honor the Daoist master Zhang Sanfeng. Historical records indicate that the name Yuzhen Palace originated from Zhang Sanfeng, who built a thatched hut named “Yuzhen Palace” at the foot of Wudang Mountain during the late Yuan and early Ming dynasty. Emperor Yongle’s admiration for Zhang Sanfeng led to the construction of the palace, which was completed in the 15th year of the Yongle reign (1417 AD) and further expanded during the Jiajing period [1,2]. The Dragon and Tiger Hall, located at the main entrance to the inner palace complex, along with other structures like the main hall (Zhenwu Hall) and side halls, forms a complete architectural courtyard. The paintings on the Dragon and Tiger Hall are typical of the early Ming dynasty’s official style, known as “Xuanzi” paintings, characterized by their sophisticated craftsmanship and use of natural mineral pigments. In 2005, due to the impact of the South-to-North Water Diversion Project, the relocation of Yuzhen Palace was initiated. Over the course of 14 years, the site was elevated by 15 m, successfully preserving the original wooden components of structures such as the Dragon and Tiger Hall and the east and west side halls, and ensuring their placement in their original positions. Despite being entirely relocated, the original paintings on the wooden beams of the Dragon and Tiger Hall exhibit clear characteristics of early Ming dynasty style. These paintings are potentially the only surviving wooden painted structures from the Ming dynasty in the Wudang Mountain area, making them invaluable for historical, artistic, and research purposes.

The Yingzao Fashi from the Song dynasty and the Gongbu Gongcheng Zuofa from the Qing dynasty are the most significant extant ancient texts documenting the decorative paintings and coatings of traditional Chinese architecture, synthesizing the essence of architectural paintings prior to the Qianlong era of the Qing dynasty. Traditional Chinese architectural paintings are primarily divided into three components: structural wooden elements, the ground layer, and pigments [3,4,5].

In traditional Chinese architectural paintings, a variety of pigments were used. For blue, pigments included azurite (2CuCO₃·Cu(OH)₂), ultramarine ((Na,Ca)₈(AlSiO₄)₆(SO₄,S,Cl)₂), Prussian blue (Fe₄[Fe(CN)₆]₃), indigo (C₁₆H₈N₂Na₂O₈S₂), and phthalocyanine blue (C₃₂H₁₀CuN₈). For green, pigments included malachite (CuCO₃·Cu(OH)₂), atacamite (Cu₂(OH)₃Cl), Paris green (Cu(CH₃COO)₂·3Cu(AsO₂)₂), Scheele’s green (Cu(AsO₂)₂), and phthalocyanine green (CuC₃₂N₈Cl₁₆). For red, pigments included cinnabar (HgS), minium (Pb₃O₄), and red ochre (Fe₂O₃). For yellow, pigments included realgar (As₄S₄), orpiment (As₂S₃), and litharge (PbO). For white, pigments included lead white (2PbCO₃·Pb(OH)₂), calcite (CaCO₃), cerussite (PbCO₃), and anglesite (PbSO₄). For black, pigments included carbon black (C), iron black (Fe₃O₄), and lead dioxide (PbO₂). These are the primary pigments commonly used in ancient architectural paintings [6]. In addition to pigments, the pigment layer also contains binders. The main binders used in traditional Chinese architectural paintings included proteins such as animal glue, egg whites, and gelatin; drying oils such as tung oil and linseed oil; waxes such as mineral wax and plant wax; polysaccharides such as gum arabic, pectin, and flour; and natural resins such as rosin and lacquer [7,8].

Modern material analysis techniques have played a significant role in the study of ancient wall painting components and processes. Techniques such as optical microscopy (OM) [9,10,11], Raman spectroscopy [12,13], infrared spectroscopy (IR) [13,14,15], X-ray diffraction (XRD) [12,16], X-ray fluorescence (XRF), thermogravimetric analysis–differential scanning calorimetry (TG-DSC), and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX) [12,16] are widely applied in the research of materials used in ancient wall paintings and polychrome decorations. The study on the decorative materials of the Drum Tower in Xi’an demonstrated that the materials and techniques used were consistent with historical records, with tung oil identified as a binder [5]. Similarly, Ling et. al identified the pigments and binders in the Guangyuan Thousand-Buddha Grotto of the Tang dynasty using OM and SEM-BSE, discovering the use of mineral pigments such as azurite, malachite, and cinnabar as well as organic binders [17]. The research on the wall paintings of Samye Temple in Tibet employed multiple analytical techniques to study the pigments and paint layer structures [18]. This study identified various inorganic pigments and organic binders, revealing the intricate methods used by ancient artists to achieve the vibrant colors and durable finishes observed in the paintings. A comprehensive study of mural paintings from an ancient Ming dynasty tomb in Jiyuan, China, used a multi-analytical approach including OM, SEM-EDX, and XRD to analyze the stratigraphy and composition of paint layers [19]. The results indicated the use of traditional Chinese painting materials, including natural mineral pigments and animal glue binders. Overall, these studies demonstrate that a thorough understanding of the materials and techniques used in historical artworks, combined with a comprehensive analysis of their current condition, is essential for effective conservation. The integration of historical knowledge with advanced analytical techniques provides a robust framework for preserving cultural heritage, ensuring that these artworks can be appreciated by future generations.

This study focused on analyzing the decorative paintings from the Dragon and Tiger Hall to understand their stylistic features, material composition, and craftsmanship. By employing techniques such as optical microscopy, scanning electron microscopy (SEM), Raman spectroscopy, and infrared spectroscopy, the research aimed to provide scientific data that support the conservation and restoration of these historical artifacts. The findings contribute to the preservation of these significant relics for future generations by providing detailed insights into the materials and techniques used in their creation. This information is crucial for developing precise conservation strategies that maintain the integrity and authenticity of the artworks. Additionally, our research highlights the unique value of the Ming dynasty’s cultural heritage, inspiring greater public awareness and enthusiasm for the protection of these cultural treasures.

2. Materials and Methods

2.1. Description of the Dragon and Tiger Hall Paintings

The Dragon and Tiger Hall is located on the north side of the Yuzhen Palace Gate and serves as the main entrance to the inner palace complex. The Dragon and Tiger Hall, together with the main hall (Zhenwu Hall), the east and west side halls, and the corridor pavilions, are all constructed on a tall platform, forming a complete architectural courtyard of the inner palace area.

The Dragon and Tiger Hall is structured with a facade of three rooms and a depth of two rooms, featuring a single-eave hip-and-gable roof. The floor plan is organized with an inner and outer central hall layout. The main entrance has a solid wood door, and the east and west side rooms once housed statues of two deities, the Azure Dragon and the White Tiger, which are now missing. The rear eaves connect to the inner palace’s corridor buildings. The beam framework uses a five-purlin central pillar system with inner and outer double beams. Under the eaves, there are single-bracket-arm, three-stepped brackets. The double beams support pedestal brackets that carry the intervening brackets, which connect to the single beams supporting the main ridge purlin. The single and double beams insert into the central pillars, with the central pillars using complex joinery to support the ridge purlin. Overall, the structure is simple and clear. After relocation, the original painted components were restored to their original positions and appearances. Missing parts were replaced with new wood, left unpainted, making it easy to distinguish between the old and new components, as shown in Figure 2.

Through detailed inspection, it was discovered that the Dragon and Tiger Hall, the inner and outer eaves of the East Wing Hall, and the outer eaves of the West Wing Hall at Yuzhen Palace still retain remnants of painting. The paintings on the beams of the Dragon and Tiger Hall exhibit clear characteristics of early Ming dynasty’s official style, known as “Xuanzi” painting. It can be preliminarily concluded that these are original official-style paintings from the early Ming dynasty. This makes them possibly the only surviving example of early Ming dynasty official wooden painted structures in the Wudang Mountains area, and such examples are extremely rare nationwide. Consequently, they hold significant historical and artistic value.

As shown in Figure 3, the paintings found on the beams of the Dragon and Tiger Hall in Yuzhen Palace exhibit specific stylistic features as follows: The paintings are divided into three sections with uneven proportions, differing from the strictly equal three-part division seen in the Qing dynasty. The end sections conclude with an auxiliary gu-head, and the central section is adorned with narrow ruyi-patterned panels. The spiral flowers are composed of a central eye and petals. On the beams, the central eye features an inverted lotus supporting a pomegranate motif, with the first row consisting of eight phoenix wing petals and the second row having ten spiral-patterned petals with embraced petals at the waist. On the purlins, the central eye is an inverted lotus supporting a ruyi motif, surrounded by ten spiral-patterned petals. Depending on the length of the components, combinations include one whole and two broken sections, one whole and two broken sections plus a layer of scroll grass, and joyful encounters. The empty square heart does not feature any patterns, and the square heart head is characterized by a three-fold wave. The overall painting follows a three-level shading technique, with bold outlines emphasized in ink. The design aligns with the basic characteristics of early Ming dynasty decorative paintings, featuring vertical and horizontal symmetry and a focus on harmony and balance in composition. The patterns are neat and elegant, with minimal ornamentation within the square heart of the beams and purlins. The primary motif within the border is the spiral flower pattern, with the old gu-head used to conclude the design. The motifs are highly realistic, with a composition that is both free and rich in detail [20,21].

The location and distribution of the painted wooden components on the beams of the Dragon and Tiger Hall are shown in Figure 4. These painted components are primarily concentrated in the front-eaves area. During the relocation and reconstruction of the Dragon and Tiger Hall, these painted wooden components were not cleaned or restored but were instead reinstated directly in their original positions. Despite some paintings being darkened and the overall condition not being very good, the main elements of the paintings remain clearly distinguishable. The stylistic features are typical of early Ming dynasty official Xuanzi paintings. The composition is consistent with the decorative style of the Wudang Taihe Palace Golden Roof paintings, suggesting that they are original pieces from the construction of Yuzhen Palace during the Yongle period.

2.2. Sampling Locations

In the western side room and the main hall of the front eaves, samples of the original paintings were collected. Specifically, samples were taken from the inner beam and bracket set of the western side room and from the blue, green, black, and red areas of the walking board near the main entrance. Using a small knife, a minimal amount of sample was gently scraped from damaged areas to minimize damage to the artifacts. Efforts were made to collect relatively intact pieces to better observe the microstructural layers of the pigments and analyze the painting techniques. As shown in Figure 5, samples were collected from two locations on the inner beam of the western side room’s front eaves, three locations on the brackets of the western mountain side of the front eaves, and two locations on the walking board near the main entrance, resulting in a total of seven samples with color remnants from three different locations.

As shown in Figure 6 and Figure 7, after collection, the samples were numbered and recorded. A total of seven samples were collected, including five pigment samples and two oil-painted samples, and were sequentially numbered from sample no. 1 to sample no. 7. The colors of the samples were visually identified: two green samples, two blue samples, one black sample, and two red samples.

2.3. Experimental Methods

(1)

Cross-Sectional Microscopic Analysis

Ultraviolet-curable resin was injected into small rectangular molds, and the samples were placed in different molds according to their numbers for embedding. The molds were then placed in an ultraviolet curing machine and irradiated for 30 min to cure the resin. After curing, the small resin blocks containing the samples were removed and ground on 320-grit sandpaper to expose the observation surface. The samples were subsequently polished on sandpapers with grit sizes of 1500, 2400, 4000, 6000, 8000, and 12,000 to obtain a smooth observation surface. After sample preparation, the samples were placed on a slide with clay at the bottom, pressed flat, and observed under a Leica DM4000M reflective polarizing microscope equipped with a 10x objective lens and a high-resolution CCD camera for image capture.

(2)

Micro-Raman Spectroscopy Analysis

A Renishaw-inVia laser confocal micro-Raman spectrometer (Renishaw, London, U.K.) was used for the analysis. The excitation light sources had wavelengths of 532 nm, 633 nm, and 785 nm, with the laser power set to 10 mW. The resolution was 4 cm⁻¹, and the measurement range was 100–3000 cm⁻¹.

(3)

Infrared Spectroscopy Analysis

Infrared spectroscopy can simultaneously provide information on both inorganic and organic substances within samples, making it suitable for analyzing the composition of the ground layer and the adhesives in gilding. For this analysis, a Thermo Fisher iN10 Mx Fourier Transform Infrared (FTIR) spectrometer with an MCT detector was used. The samples suspected of containing ground layers (samples no. 6 and no. 7) were scanned. The scanning range was 4000–675 cm⁻¹, with a resolution of 4 cm⁻¹ and 64 scans per sample.

(4)

SEM-EDX Analysis

Scanning electron microscopy (SEM, Zeiss Gemini 300, Oberkochen, Germany ) combined with energy-dispersive X-ray spectroscopy (EDX) was utilized to analyze the microstructure and elemental composition of the pigment samples. The SEM provided detailed images of the surface morphology at an accelerating voltage of 5 kV, while the EDX performed elemental analysis using a silicon drift detector at a working distance of 10 mm. The samples were mounted on aluminum stubs using conductive adhesive and coated with a thin layer of platinum (approximately 10 nm thickness), using a sputter coater to prevent charging under the electron beam.

3. Results and Discussion

3.1. Cross-Sectional Microscopic Analysis

The cross-sectional microscopic images of the painted samples are shown in Figure 8. The cross-sectional microscopic analysis revealed that sample no. 1 consists of a bottom layer of green pigment directly applied to the wooden component with no ground layer, covered by an upper layer of dust and contaminants. Sample no. 5 shows a bottom thin ground layer, a middle layer of blue pigment, and an upper layer of dust and contaminants. Sample no. 7 is composed of a bottom ground layer, followed by a yellow-brown layer (likely an initial oil undercoat), a red pigment layer, and an upper layer of contaminants.

3.2. Raman Spectroscopy Analysis

Based on the sampling locations and the characteristics of the samples, further analysis of the pigments in samples no. 2, no. 3, no. 4, no. 6, and no. 7 was conducted using Raman spectroscopy. By comparing the Raman spectra with published databases of mineral or synthetic pigments [22,23,24,25], the specific types of pigments used were identified.

The Raman spectra for samples no. 2 and no. 4 are shown in Figure 9. The Raman spectrum for the blue pigment no. 2 from ancient paintings exhibits prominent peaks at 116 cm⁻¹, 247 cm⁻¹, 398 cm⁻¹, and 1093 cm⁻¹, as shown in Figure 9a. These peaks suggest the presence of azurite (Cu₃(CO₃)₂(OH)₂), a common blue pigment used in ancient artworks. The peak at 116 cm⁻¹ corresponds to lattice vibrations, while the peaks at 247 cm⁻¹ and 398 cm⁻¹ are indicative of bending modes of the carbonate ions within the azurite structure. The significant peak at 1093 cm⁻¹ is associated with the symmetric stretching vibrations of the carbonate groups. Azurite was favored in ancient times for its vibrant blue color and stability. On the other hand, pigment no. 4 (Figure 9b) showed prominent peaks at 150 cm⁻¹, 181 cm⁻¹, 218 cm⁻¹, 271 cm⁻¹, 353 cm⁻¹, 432 cm⁻¹, 533 cm⁻¹, 1054 cm⁻¹, and 1098 cm⁻¹. These peaks indicate a mixture of malachite (Cu₂(CO₃)(OH)₂), azurite (Cu₃(CO₃)₂(OH)₂), and possibly chrysocolla [5,26]. Malachite and azurite are well-known green and blue pigments, respectively, with chrysocolla adding a blue-green hue. These identifications align with historical uses of these pigments in ancient painting art. Malachite is a widely distributed copper carbonate hydroxide mineral found on the Earth’s surface. Azurite often coexists with malachite and can be used as a blue pigment or even as a glass protective material [27]. In ancient times, people used malachite or azurite to produce blue pigments and also obtained green pigments from malachite.

The Raman spectra for samples no. 6 and no. 7 are shown in Figure 10. Pigment no. 6 showed significant peaks at 224 cm⁻¹, 294 cm⁻¹, 407 cm⁻¹, and 610 cm⁻¹ (Figure 10a). These peaks suggest the presence of hematite (Fe₂O₃), which is commonly used as a red pigment in ancient art. The Raman spectrum for the pigment no. 7 from ancient paintings exhibited significant peaks at 254 cm⁻¹, 285 cm⁻¹, and 342 cm⁻¹, as shown in Figure 10b. These peaks suggest the presence of vermilion (HgS), a common red pigment used in ancient artworks [28]. The peak at 254 cm⁻¹ corresponds to the stretching vibrations of the Hg-S bond, which is a distinctive feature of cinnabar. The additional peaks at 285 cm⁻¹ and 342 cm⁻¹ are also indicative of the vibrational modes associated with mercury sulfide. Cinnabar was favored in ancient times for its vibrant red color and stability [29].

The Raman spectra for sample no. 3 are shown in Figure 11. The Raman spectrum for the black pigment no. 3 from ancient paintings reveal significant peaks at 1333 cm⁻¹ and 1596 cm⁻¹. These peaks are characteristic of carbon-based materials, specifically indicating the presence of amorphous carbon or carbon black. The broad peak at 1333 cm⁻¹, known as the D-band, is attributed to disordered graphite or defects within the carbon structure, while the peak at 1596 cm⁻¹, known as the G-band, corresponds to the in-plane vibrational modes of sp²-bonded carbon atoms in graphitic materials. The overall trend shows a high intensity around these peaks, suggesting a significant amount of carbon content in the pigment. The use of carbon-based pigments, such as carbon black, was common in ancient artworks for producing black colors due to their stability and strong absorption properties. The Raman peak wavenumbers of all samples and their corresponding pigment types are shown in

Table 1. The summary of Raman peak wavenumbers.

Sample No.	Wavenumber (cm−1)	Peak Assignment	Ref.
2	116	Azurite	[30]
	247, 398
	1093
4	150, 181, 218	Malachite/Azurite	[30]
	271, 353, 432
	1054, 1098	Chrysocolla	[31]
6	224, 294	Hematite	[32]
	407, 610
7	254, 285, 342	Vermilion	[23]
3	1333, 1596	Carbon black	[33]

.

3.3. Scanning Electron Microscopy (SEM) Analysis

The SEM images (Figure 12a,e) show the surface texture and particle distribution of the pigments. The images reveal a varied microstructure across different samples, with some showing a more granular texture and others appearing smoother and more compact. Sample no. 2 (Figure 12a) and sample no. 4 (Figure 12b) exhibit relatively rough textures with visible particle agglomerates, suggesting the use of mineral pigments.

Sample no. 5 (Figure 12c) and sample no. 7 (Figure 12d) show a smoother surface, indicating a finer particle distribution, which might be due to the presence of organic binders or a different preparation technique. Sample no. 3 (Figure 12e) appears more compact, suggesting a homogenous mixture of its components.

The EDX analysis revealed the elemental composition of each sample, providing insights into the pigments’ chemical nature (

Table 2. Elemental composition of paintings pigments by SEM-EDX.

	Atomic Percentage (at%)
	C	O	Si	S	Ca	Cu	Hg	Fe
No. 2	26.5 ± 2.8	58.9 ± 2.6	-	3.0 ± 0.9	-	20.8 ± 4.1	-	-
No. 4	26.0 ± 2.6	56.1 ± 4.0	-	1.1 ± 0.1	-	17.1 ± 2.0
No. 6	53.9 ± 2.7	46.2 ± 10.9	-	-	3.0 ± 1.1	-	-	25.3 ± 9.4
No. 7	25.3 ± 4.7	55.2 ± 6.9	-	17.8 ± 2.0	-	-	1.73 ± 0.8	-
No. 3	45.8 ± 5.5	51.8 ± 4.8	1.3 ± 0.7	1.2 ± 0.4	3.8 ± 0.7	1.3 ± 0.4	-	-

). Sample no. 4 (green pigment) also showed high Cu and Ca levels, consistent with copper-based green pigments like malachite. In sample no. 6 (red pigment), the high iron (Fe) content (43.47%) indicates the use of iron oxide pigments such as hematite. Sample no. 7 (red pigment) shows high carbon (C) and oxygen (O), suggesting an organic binder like tung oil, with mercury (Hg) and Fe indicating cinnabar and possibly hematite. Sample no. 3 (black pigment) has high C and O levels, pointing to carbon black. This is consistent with the results of the Raman and infrared spectroscopy analyses. These trends reflect the use of both mineral and organic components in ancient pigments, highlighting the sophisticated techniques employed by ancient artists.

3.4. Infrared Spectroscopy Analysis

The Raman peak wavenumbers of all samples and their corresponding pigment types are shown in Figure 13 and

Table 3. The summary of infrared spectroscopy band wavenumbers.

Wavenumber (cm−1)	Assignment	Ref.
2920, 2850	C-H stretching vibrations (organic materials)	[34]
1400	Carbonate ion (calcium carbonate, CaCO3)	[35]
1000–1100	Silicate substances (from basement layer)	[36]

. The infrared spectrum of the ground layer of paintings sample no. 7 exhibited distinct absorption bands that provide insights into its composition. The prominent peaks around 2920 cm⁻¹ and 2850 cm⁻¹ correspond to the C-H stretching vibrations, indicative of organic materials, specifically oils. The broad absorption band around 1400 cm⁻¹ is characteristic of the carbonate ion, suggesting the presence of calcium carbonate (CaCO₃). Prominent absorption bands around 2920 cm⁻¹ and 2850 cm⁻¹ are associated with the C-H stretching vibrations, which suggest the presence of organic materials, likely tung oil. The significant peaks in the region of 1000–1100 cm⁻¹ indicate the presence of silicate substances, which may originate from the basement layer adhered to the oil-painted layer. The Raman spectrum confirmed that the pigment used in sample no. 7 is cinnabar, indicating that the oil-painted layer may have been composed of tung oil mixed with cinnabar. The combination of tung oil with mineral pigments such as cinnabar and iron red was historically used to create durable and vibrant paint layers.

4. Conclusions

The analysis of the paintings on the wooden beams of the Dragon and Tiger Hall at Yuzhen Palace, Wudang Mountain, provided significant insights into the materials, techniques, and historical context of these early Ming dynasty artworks. Using a combination of optical microscopy, SEM-EDX, Raman spectroscopy, and infrared spectroscopy, the study identified that the pigments used are all natural minerals, including azurite, malachite, vermilion, and hematite. These findings are consistent with historical records of pigment use during the early Ming dynasty, indicating the paintings are typical official Xuanzi paintings, as shown in

Table 4. Summary of pigment types used in cultural heritage buildings.

Location	Building	Period	Pigment	Ref.
Wudangshan, China	Yuzhen Palace	Ming	Blue—azurite, Green—malachite, Red—vermilion and hematite	-
Beijing, China	Palace Museum	Qing	Green—auramine O and malachite green. Blue and cyan—methylene blue, methyl violet, rhoduline blue, and crystal violet. Red—eosin Y	[37]
Beijing, China	Jiangxue Palace	Ming	Emerald green, lead white, and lead red (minium).	[38]
Beijing, China	Wuying Hall	Ming	Lampblack, ultramarine blue/lapis lazuli, dolomite, emerald green, and gypsum.	[39]
Guangyuan, China	Thousand-Buddha Grotto	Tang	Green—malachite and atacamite, Red—minium, hematite, and cinnabar, Blue—lazurite and organic blue materials, White—anglesite and gypsum.	[17]
Tibet, China	Jokhang Temple	Tang	Cinnabar, malachite, azurite, orpiment, red lead, synthetic ultramarine blue, and emerald green.	[29]
Yixing, China	Taiping Heavenly Kingdom Royal Residence	Qing	Vermilion, graphite, white lead (2PbCO3·Pb(OH)2), and lead red (Pb3O4).	[16]
Shaanxi, China	Cangjie Temple	-	Cinnabar, lapis lazuli, lead white, Paris green, and carbon black.	[40]

. The structural analysis revealed that the paintings were applied directly onto wooden components without a ground layer, using ink lines for outlining and a thin ground layer made of tung oil mixed with lime under the oil coating. This technique underscores the sophisticated craftsmanship and the historical value of these decorations.

This research not only confirms the historical authenticity of the Dragon and Tiger Hall’s paintings but also provides crucial scientific data to support the conservation and restoration efforts of the Yuzhen Palace architectural complex. The identification of original Ming dynasty materials and techniques contributes to the broader understanding of Chinese cultural heritage and the preservation of ancient artworks. By preserving and restoring these significant cultural relics, the study ensures that the historical and artistic legacy of the Wudang Mountain architectural complex continues to be appreciated by future generations.