Skip to main content
Heritage Science
Download PDF
Download ePub

Chromogenic mechanisms of overglaze yellow pigment produced in Jingdezhen imperial kilns during the Ming dynasty

Heritage Science volume 12, Article number: 343 (2024) Cite this article

Abstract

This study employed energy-dispersive X-ray fluorescence spectrometry, Raman spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible-near infrared spectrophotometry to analyse eleven overglaze pigment porcelain specimens. The results show that the colouring element of the overglaze yellow pigment of Jingdezhen imperial kilns in the Ming dynasty is Fe2O3, and most of Fe2O3 can be dissolved in the lead glaze in an ionic state to make the lead glaze yellow. The chromogenic of the overglazed yellow pigment primarily depends on the concentration and coordination field of the colouring ions. The connection between the internal structure and the appearance of the overglaze yellow pigment is discussed.

Introduction

During the Ming (1368-1644 CE) dynasties, Jingdezhen in Jiangxi Province was the centre of China’s porcelain industry, and it earned the reputation of being the ‘origin of all kiln-fired wares under the sun’. A vast array of porcelain decoration styles, such as Doucai (contrasting colours) and Wucai (polychrome), were developed in the city, marking the beginning of the coloured porcelain era in the history of Chinese porcelain. Overglaze pigments are available in various of hues, such as red, green, yellow, violet, blue, and black. Among the different colours, yellow was the favourite colour of the ancient emperors. The development of overglaze yellow pigment during the Ming dynasty in Jingdezhen exhibited rapid advancement, as evidenced by extant artefacts and archaeological discoveries. This period introduced several new hues, such as ‘goose yellow’, ‘apricot yellow’, ‘beeswax yellow’, and ‘ginger yellow’ [1]. These colours became the principal components of the ceramic overglaze pigments.

Instrumental analysis of the Chinese overglaze pigment has been carried out for more than 140 Years. The scientific and technological analysis of overglaze yellow pigment indicates that lead-based yellow pigments can be traced back to about 1600 AD. In the following centuries, yellow pigments have been continuously developed, and they are mainly classified into lead-based yellow, lead-tin yellow, lead-antimonate yellow and lead-antimony-tin yellow (Pb-Sn-Sb triple oxide yellow), etc. [2, 3]. Zhang [4] initially identified overglaze as part of the PbO-SiO2-K2O ternary system for Chinese overglaze yellow pigments. They revealed that the only type of overglaze yellow pigment used was iron-based yellow before the Kangxi period. After the Kangxi period, antimony yellow emerged, with antimony oxide as the primary colourant. Zhang et al. [5] conducted a compositional analysis on the body, glaze, and decoration of samples excavated from an imperial kiln of the Chenghua era. They discovered that Fe2O3 was the chromogenic agent in the overglaze yellow pigment. However, elevated CuO levels because the studied artefacts had been buried for extended periods complicated the interpretation of the chemical composition. Chen [6]analysed overglaze yellow pigment on Chenghua Doucai porcelain and porcelain with contrasting colours using Raman spectroscopy, suggesting the possible presence of hydroxyapatite [Ca3(PO4)2]. Zhao et al. [7] employed various techniques, including X-ray fluorescence spectrometry and Raman spectroscopy, and detected the presence of Fe and Cu in the overglaze yellow pigment of Jingdezhen porcelain produced during the Ming and Qing dynasties. They also identified Raman peaks for quartz, PbO, and corrosion products in Doucai porcelain from the Ming dynasty. However, severe weathering in porcelain with yellow pigment from the Qing dynasty rendered many details unclear. Wu et al. [8]employed Raman spectroscopy in conjunction with energy dispersive X-ray fluorescence (ED-XRF) spectrometry and identified that lead-tin yellow was used as a chromogenic reagent in overglaze yellow pigment in Jingdezhen porcelain during the Qing dynasty (1650-1660). This result represents the earliest clear example of using tin-based chromophores in Chinese ceramic technology. He et al. [9] similarly used EDXRF to study a variety of Qing dynasty overglaze pigment and noted the use of antimony in famille rose. Miao et al. [10] point out that three types of overglaze yellow pigments make up Chinese overglaze pigment porcelain from the late Kangxi period to AD 2007: lead-tin yellow, lead antimonate yellow and lead-antimony-tin yellow, and reported on the historical dating of these pigments, which further supports Kingery and Vandiver’s [11] conclusion that lead stannate was the main colourant for 18th-century overglaze yellow pigment.

Colomban [12, 13] showed that lead-based pyrochlore solid solutions appeared side by side with iron oxide for porcelain decoration at least from the mid-seventeenth century, as also observed in previous works that placed the use of such compounds after the Ming dynasty. Iron oxide has been used since the late Warring States period to produce a yellow pigment in an oxidising atmosphere [14]. However, the technique of overglaze yellow pigment began in the fifteenth century AD. The overglaze yellow pigment at Jingdezhen is documented in two letters from Dentrecolles [15, 16]. Later, artisans mostly followed this recipe; in the mid-nineteenth century, Ebelmen and Salvétat[17]pointed out the problems associated with the raw material for overglaze pigments. Jiang [18], drawing on knowledge from historical records, noted that red materials were invented first among the red, yellow, and green overglaze pigments. Overglazed yellow pigment, developed later, was based on iron red. However, graphite powder and iron were added to colour it. Using simulations and archaeological data from the Chenghua period, Jiang [19] demonstrated that overglaze red pigment was often applied over overglaze yellow pigment; the entire piece was fired at a low temperature, enabling layered decorative effects. Hao [20] also highlighted the use of yellow base with red overpainting, a technique known as ‘yellow under red’ that started in the Chenghua period. After the Kangxi period, unsatisfied with the warm but dull hues afforded by iron oxide, brighter and cooler shades of yellow were soon achieved by enamellers using lead-stannate and lead-antimonate compounds.

Despite the widespread use and innovation of overglaze yellow pigments, the chromogenic mechanism of the oldest overglaze yellow pigment is not well understood or even known. Ceramic pigments manufactured before the mid-nineteenth century, due to the use of raw materials that were not fully purified (ores or metallic minerals, etc.), the relevant information about the origin of the raw materials, the production process, the compositional formulas, etc., remained in the final colours, which were either dissolved in the primary phase or existed in the form of crystalline substances. We have demonstrated that the chromogenic element of overglaze yellow pigment is Fe2O3, and the hue range of the pigments depends on the elemental composition, process technology, firing temperature and atmosphere, etc. [21] Energy-dispersive X-ray fluorescence spectroscopy and microscopic Raman spectroscopy can be achieved to obtain non-invasively the information on the elemental composition [9] and crystal structure [11, 22] of overglaze yellow pigment, but more scientific and technological analyses are needed to comprehensively understand the chromogenic mechanism of overglaze yellow pigment. The ability of overglaze pigments to present different colours depends on the selective absorption and reflection of visible light by the colouring elements. When excited by electromagnetic waves, different substances have different absorption, reflection and transmission spectra. The intensity of the absorption spectrum can reflect the structure and content of the colouring elements, while the curve of the reflection spectrum can be used to measure the reflective colours of the samples and accurately characterise their visual differences. The chromogenic effect of overglazed yellow pigment is believed to be mainly related to the valence and coordination states of the colouring substances. In recent years, the use of UV-vis-NIR spectroscopy to analyse the state of coordination compounds formed by ions and ligands in enamel or glass, and thus analyse the mechanism of its colouration has been very mature, which plays an vital role in the nondestructive analysis of rare archaeological samples according to the optical properties of substances [23]. At the same time, it is also necessary to cooperate with X-ray photoelectron spectroscopy to be the first to determine the valence ratio of the colouring ions. Not all the techniques described below were used for all the fragments, owing to the scarcity of the original material. The purpose of this study is to establish the relationship between the internal structure and their appearance by comparing the composition formula, the content of colouring oxides, the state of existence of the colouring elements of the overglaze yellow pigment of the Jingdezhen Imperial kiln in different periods of the Ming dynasty. This study contributes to the comprehensive understanding of the technological essence of overglaze yellow pigment during the Ming dynasty. It provides a scientific basis for discussing the development trajectory of overglaze yellow pigment and their replication. Moreover, it offers a valuable methodological reference for future scientific studies in overglaze pigments.

Samples and methods

Samples

Table 1 lists the photographs, dates and some of the excavation dates of 11 samples of overglaze yellow pigment excavated from the Jingdezhen Imperial Kiln Factory during the Ming dynasty, all provided by the Jingdezhen Imperial Kiln Museum in Jiangxi Province. The major elements of overglaze yellow pigment were measured by XRF spectroscopy, while the colour analysis of the samples was listed in Table 1 based on the chromaticity values that are defined in the CIE-lab colour space. The chromaticity value data and the compositional data of the underlying glaze are recorded in the supplementary material.

Table 1 List of the 11 overglaze yellow pigment porcelains
Full size table

Analytical methods

ED-XRF spectrometry

Specimens were cleaned in a CQ-250 ultrasonic cleaner for 20 min and dried in a 101–1 electric forced-air drying oven. Subsequently, the elemental compositions of the overglaze yellow pigment from the Ming dynasty were determined using an EAGLE III XXL XRF spectrometer (EDAX Inc., USA) using the following parameters: X-ray tube pressure of 50 kV, tube current of 200 μA, beam path in vacuum, and an incident X-ray beam spot diameter of 300 μm. The measurement was performed on the surface of the samples, and each location was tested using triplicate. Semi-quantitative analysis was conducted using the in-built standardless fundamental parameter method. There are two reasons for semi-quantitative analysis: one is that the nature and state of the sample and its surface varies significantly; the overglaze-pigment belongs to the low-temperature lead glaze system; the specimen contains high lead content, giving a high error that affects the other trace elements when deconvoluting the spectrum and the quantitative analysis of the elemental composition is more difficult to carry out in the low-energy region, mainly in the high-energy region of the measured spectrograms. Secondly, the amount of laser stripping when using ED-XRF to detect the composition of the overglaze pigment is enormous; the high-energy X-ray photons can penetrate relatively deeply (tens of micrometers) into the material, depending on the energy of the X-ray beam and absorption coefficients of the components of the analyte [24]. Because the penetration depths of light elements (Mg, Al, Si, K and Ca) are close to the surface, whereas the penetration depths of heavier elements such as lead (Pb) are more than hundreds of micrometres, and those of tin (Sn) and antimony (Sb) are more than a few millimetres [25], the collected photons may come from the overglaze-pigment layer and the underlying high-temperature glaze, resulting in the Si and Al contents being relatively high and Pb content relatively low in a relatively high content of Si and Al and a relatively low content of Pb. Additionally, when calculating the elemental composition of a sample using an online calculator for XRF signals, the software automatically selects the line used to quantify the content, usually the K line; however, when considering Pb, which is used on the surface of the overglaze, the L line must be selected for quantification. The variability in the data results did not affect the comparative study of the relative elemental content of the overglaze pigment, following a rigorous evaluation of the relevant XRF data.

Raman spectroscopy

An in Via micro confocal Raman spectrometer from Renishaw (UK) was used to characterise the crystalline species of the overglaze pigments. A highly stable 532 nm fixed laser and its corresponding filter assembly were used for the study, with a throughput efficiency of more than 30%. The equipmen is fitted with a Leica microscope from Germany, an advanced feedback-controlled ultra-high precision diffraction grating turntable and patented continuous scanning technology. Because overglaze pigments may undergo profound thermal changes when exposed to high-intensity radiation [26, 27], the output power of the test was 50 mW and the power of the sample level was 0.2 mW to avoid heating the samples, and the laser beam was focused perpendicularly to the sample surface with a × 50 microscope objective; The spot diameter is about 5–10 µm. The spatial resolution was 0.5 μm in the horizontal direction and 2 μm in the vertical direction. Due to the optics used, the volume analysed is controlled at the micronscale, i.e., much smaller than the one probed by X-ray fluorescence. Therefore, there is no contribution from the underlying materials, the volume probed by Raman microspectroscopy being at the very surface. The acquisition time for each spectrum was approximately 60 s, and was recorded over the range of 50–2000 cm−1, with a spectral resolution of 1 cm−1.The instrument was calibrated by using a single-crystal Si specimen before testing. For the yellow pigment region in the object, a minimum of three Raman spectra were recorded to ensure representative data. The data was processed with Origin 2022 software.

XPS analysis

Using the Thermo Scientific K-Alpha XPS from the United States, overglaze samples were prepared into blocks of dimensions 5 mm × 5 mm × 5 mm. The samples were introduced into the analysis chamber; the pressure was maintained at values < 2.0 × 10–7 mbar. The spot size was 400 μm, the working voltage was 12 kV, and the filament current was 6 mA. A full-spectral scan was conducted at 150 eV with a step size of 1 eV; a narrow-spectral scan was conducted at 50 eV with a step size of 0.1 eV. The XPS data were analysed using the Advantage software programme for peak fitting and valence state calibration.

UV–vis-NIR analysis

The Shimadzu UV-3600I PLUS UV–vis spectrophotometer from Japan was employed to analyse specific areas of the overglaze pigment surface, which is non-destructive to the specimen. The spot size was 5 × 5 mm, and the spectral range was set from 200 to 2000 nm, with reflectance spectra collected from 400 to 700 nm and absorption spectra from 200 to 2000 nm. The data interval was 2 nm. The scanning speed was medium, and the grating converted to a wavelength of 720 nm. After the baseline scanning with the BaSO4 standard white plate, the samples were fixed with the fixture, and the test site was aligned with the integrating sphere sample window. Spectral data were analysed using the LabSolutions UV–vis software programme provided with the instrument. In this case, the solid UV samples were tested using the integrating sphere because the data in absorption mode is a converted signal through reflection. When the samples are too dark, it can lead to a significant turn at 726 nm due to the colour of the sample being too different from the background. Five representative samples were selected for the study, and the centre of the scan was aligned with the test site whenever possible to ensure the accuracy of the experimental data.

Results and discussion

Information on the elemental composition

Table 2 displays the EDXRF results for the overglaze yellow pigment samples. To visually identify the variations of the significant elements in the spectrum of the overglaze yellow pigment, we can use the information obtained from looking at the scatter plot of the SiO2 and PbO content (Fig. 1a) and the scatter plot of the PbO and Fe2O3 content (Fig. 1b). The overglaze yellow pigment of ceramic pieces unearthed from the Ming dynasty imperial kilns predominantly contain SiO2 and PbO. According to the results of semi-quantitative data calculations, an inverse relationship generally exists between the SiO2 and PbO contents, as shown in Fig. 1a. The concentrations of alkali metal oxides and alkaline earth metal oxides such as K2O, Na2O, CaO, and MgO are minimal. Although MnO and TiO2 may contribute to the chromogenic outcomes, their contents are less than 0.1 wt%, and thus their influences on colouration are negligible. Iron serves as the principal colourant with concentrations ranging from 1.81 wt% to 4.87 wt% (calculated based on the content of Fe2O3). The colouring elements do not contain antimony and tin, and the colours are rendered in iron-based yellow, which is transparent, consistent with the previous findings that before the Kangxi period in the Qing dynasty, there was only one type of overglaze yellow pigment [4]. Figure 2 shows the polar coordinates of C* and h* for the overglaze yellow pigment. Combined with Fig. 1b, it can be intuitively found that the chromaticity angle (h) basically tends to increase with the increase of Fe2O3 content and the decrease of PbO content in all samples except for MMD-4. At the same time, MMD-4 has relatively low Fe2O3 content and high PbO content. The chromaticity angle is also on the large side, indicating that the concentrations of Fe2O3 and PbO are key factors affecting the chromogenic outcomes of the overglaze yellow pigment.

Table 2 Semi-quantitative X-ray fluorescence spectroscopy results for overglaze yellow pigment (wt%)
Full size table
Fig. 1
figure 1

a Scatter Plot of SiO2 and PbO Changes; b Scatter Plot of PbO and Fe2O3 Changes

Full size image
Fig. 2
figure 2

The Polar Coordinates of C* and h* for the Overglaze Yellow Pigment

Full size image

The formula of overglaze yellow pigment in Jingdezhen was documented in the Ming and Qing dynasties. In the Ming dynasty, the Jiangxi Province Da Zhi recorded [28]: “Golden yellow, with a catty of ground black lead, ochre one tael and two mas.” In the Qing Dynasty, Dentrecolles writes [16]: “As for yellow, to one tael of ceruse [white lead] add three mas and three fuen of stone powder and one fuen and eight ly of pure red that has not been mixed with ceruse.” According to research, ochre contained high levels of Fe2O3 and a significant quantity of quartz, whereas pure red [29] consisted solely of Fe2O3 [30]. In silicate ceramics, SiO2 tended to form a glassy phase with alkaline oxides at high temperatures, with iron ions absorbing oxygen from alkali metal oxides or alkaline earth metal oxides, thus forming [FeO4] groups that affect the glaze colour. Consequently, the content of silicon is typically inversely related to the levels of iron and lead. As depicted in Fig. 1b, samples from the Zhengde period exhibit part of the overglaze yellow pigment in Fe2O3 content increased significantly. This phenomenon may be related to the change of the formula. It is believed that there were two formulas for overglaze yellow pigment in Jingdezhen during the Ming dynasty: One was made from ochre and lead powder; the other comprised quartz, lead powder, and pure iron red. The latter formula appeared later, around the late Zhengde period.

Iron forms and their relationship to chromogenic outcomes

Figure 3 presents the Raman spectra of overglaze yellow pigment samples from the Jingdezhen imperial kiln during the Ming dynasty. Apart from sample MJJ-1, the Raman spectra of the other samples display a very intense low-wavelength peak region (110–130 cm−1), and this intense peak is a sign of lead-based overglaze pigments [31]. Additionally, there are "broad" bands of medium intensity at 450–500 cm−1 and 900–1100 cm−1 [32], which are caused by the bending and stretching modes of [SiO4] tetrahedra, which are the basic units of silicates, and this Raman spectrum is the characteristic spectrum of glassy silicates. When the sample surface is in a disordered glassy state, the crystal’s characteristic Raman peaks diffuse and merge, forming an envelope curve. The broad band at 450–500 cm−1 corresponds to the symmetric bending vibration of the Si–O bond, which dominates the Raman spectra of the tightly connected Si–O network [33], while the broad band at 900–1100 cm−1 represents the symmetric stretching vibration of the silicate tetrahedra (Si-Onb), which increases in intensity with the polymerisation reaction [34]. The Raman peaks in the stretching mode are characterised by different types of SiO4 tetrahedra forming silicate glass phases, i.e., isolated (Q0) tetrahedra and tetrahedra aggregated by one (Q1), two (Q2), three (Q3), and four (Q4) vertices, which are mainly correlated with the flux/SiO2 ratio, thus reflecting the melting temperature. In general, the wave number of the Q0 Raman peak is about 800 - 850 cm−1, and the wave number of the Q4 Raman peak is about 1100 - 1200 cm−1 [32, 35, 36]. Throughout the Raman spectra of the overglaze yellow pigment, the peak in the [SiO4] stretching mode is a significant feature of the Pb-rich base glaze samples, which is manifested by the fact that the fewer the Si–O bonding connections are, the lower the wave number of the stretching mode is, and the centre of gravity of the broadband of the stretching region is correlated with the melting temperature of the silicate [37]. Compared to glass silicate samples fired at high temperatures, glass silicate surfaces melted at low temperatures (< 900 ℃) show stronger intensity bands in the range of 900–1100 cm−1 [38] and whose centre of gravity shifts toward 1035 cm−1 when the lead content decreases. For the lead-free glaze, the mode is of very low intensity between 1000 and 1150 cm−1 [39]. The EDXRF analysis results indicate that the PbO content in most of the overglaze yellow pigment significantly exceeds that of Fe2O3. During firing, Fe2O3 can form iron ions that integrate into the glassy matrix, resulting in overglaze yellow pigment melting into a uniform lead-silicate glass phase, with the chromogenic effect predominantly caused by the presence of iron ions.

Fig. 3
figure 3

Raman spectra of overglaze yellow pigment

Full size image

The Raman spectrum of sample MJJ-1 reveals Raman peaks distinct from the other samples at positions 224 cm−1, 245 cm−1, 290 cm−1, 406 cm−1, 493 cm−1, 610 cm−1, 665 cm−1, and 1,317 cm−1, which are entirely consistent with the characteristic peaks of α-Fe2O3 [40]. However, at illumination powers below 0.5 mW, recrystallisation of Fe2O3 under laser action was primarily ruled out [41]. According to the compositional analysis, when the Fe2O3 content is too high and the PbO content is low, the Raman spectra show the characteristics of the crystalline phase (narrow Raman peaks) [42], indicating the presence of α-Fe2O3 crystals in the overglaze yellow–brown pigment, with the highest Fe2O3 colouring contribution attributed to ions and a smaller contribution attributed to crystals.

Further XPS analysis explored the valence states of iron ions in the overglaze yellow pigment and the impact of the relative content of Fe3+ and Fe2+ on the chromogenic outcomes. For this purpose, one specimen from each period was selected for detailed analysis. Figure 4 displays the XPS spectra of the iron element from four samples, where the Fe element in the yellow decoration primarily appears in the peaks at Fe2p3/2 ≈ 711.5 eV and Fe2p1/2 ≈ 725 eV, indicative of Fe2O3. Peak fitting of the Fe element XPS spectra from different periods using the Avantage software programme revealed electron binding energies at 710 eV and 714 eV for Fe2p3/2 (II), 712 eV, and 719 eV for Fe2p3/2 (III), 723 eV and 728 eV for Fe2p1/2 (II), and 725 eV and 733 eV for Fe2p1/2 (III) [43]. These findings indicate the coexistence of trivalent and divalent Fe elements in the overglaze yellow pigment. The relative areas of these peaks, as listed in Table 3, show that the ratios of Fe3+ to Fe2+ ions in the samples MCH-2, MMD-4, MZD-3, and MJJ-1 are 1.4, 1.88, 1.75 and 3.9, respectively. This suggests that the chromogenic effect of the overglaze yellow pigment is primarily due to Fe3+ ions and occurs in an oxidising atmosphere. An increase in the Fe2O3 or alkaline oxide content favours an increase in the Fe3+ /Fe2+ ratio.

Fig. 4
figure 4

X-ray photoelectron spectral fitting graph for fe element in overglaze yellow pigment

Full size image
Table 3 Ratio of Fe Ion contents in overglaze yellow pigment
Full size table

Figure 5 displays the UV–vis diffuse reflectance spectra of the overglaze yellow pigment samples. The results indicate significantly enhanced reflectance bands between 550 and 620 nm for the overglaze yellow pigment in Jingdezhen imperial kiln during the Ming dynasty. According to the visible light reflectance spectrum [44], the highest reflection intensity of sample MCH-2 is around 550 nm (P1). Due to the test area being larger than the yellow pigment area in the samples, the test results may be affected by the green pigment of the greenish hues, and the other samples in the overglaze yellow pigment are undisturbed. Sample MMD-4 has the highest reflection peak intensity of about 580 nm or more (P2), with a yellowish tone. Sample MZD-3 and MWL-1 have reflection peaks at about 610 nm (P3), with a deep yellow tone, while sample MJJ-1 has a significantly enhanced reflection peak in the orange-red area in addition to a high reflection peak at about 620 nm (P4), and the overall surface of the sample of MJJ-1 shows a yellow–brown appearance.

Fig. 5
figure 5

Reflectance Spectrum of Overglaze Yellow Pigment Samples

Full size image

Iron ions have unpaired electrons that can absorb spectra in certain wavelength ranges, and different valence states of iron ions have different spectral absorption properties. Fe3+ ions have ultraviolet (UV) absorption properties, Fe2+ ions have near-infrared (IR) absorption properties, and neither Fe3+ ions nor Fe2+ ions have absorption properties in the visible region [45]. However, Fe3+ ions and Fe2+ ions are always coexisting in silicate glass, and they form a Fe3+-O-Fe2+ structure, which is the actual iron silicate structure colouring the glass phase surface of the overglaze pigment [46]. According to the results of EDXRF and XPS analysis, the overglaze yellow pigment of Jingdezhen imperial kilns of the Ming dynasty were all fired in an oxidising atmosphere with the high-iron alkali silicate materials, and the iron primarily exists in the form of Fe3+. The electronic configuration of Fe3+ is 3d54S0 and coordinates with 4 and 6 O2−. Fe3+ ions can form tetrahedral [FeO4] or octahedral [FeO6]. Fe2+ has an electronic configuration of 3d64S0 and generally contributes to the chromogenic process in combination with Fe3+. In spectroscopy, the Fe3+ ion has two prominent absorption peaks: the first one is located at about 240–260 nm, which is caused by the 3d electron jump of Fe3+; the second one is located at 350–400 nm, which is related to the ligand environment of Fe3+, and the different ligands will lead to the position and width of the absorption peaks change [47]. The position of the absorption bands of the colouring ions of the same valence state is mainly related to the coordination field of the ions, the thermal reaction conditions and the cations in the vicinity of the oxygen polyhedra.

Figure 6 presents the UV–vis-NIR absorption spectrum of the overglaze yellow pigment samples. The peak at P3 represents the absorption of Fe3+-O-Fe2+, producing strong absorption effects in the NIR region [48]. When the Fe3+ content is higher than the Fe2+ content, these Fe3+ superfluous ions occupy network-modifying positions, forming Si4+-O-Fe3+ structures, adjusting the blue-green hues to yellow [47]. Peaks at P4 and P5 represent the coordination absorption peaks of Fe2+; their lower contents do not significantly impact the chromogenic result of the overglaze yellow pigment. The overglaze yellow pigments of Jingdezhen imperial kilns of the Ming Dynasty are all based on SiO2-PbO as the skeleton of the basic silicate network, and Fe2O3 as the colouring element. The study mainly investigates the effect of the coordination fields of colouring ions on the colour presentation. When the ratio of Fe3+/Fe2+ in the overglaze yellow pigment is in a specific range, the absorption peak of Fe3+ ions is mainly located at 350–400 nm, and Fe3+ ions are predominantly coloured by the O2−-Fe3+ charge transfer of the tetrahedral [FeO4] coordination in the Fe3+-O-Fe2+ structure. This structure, similar to the silicate tetrahedron [SiO4], produces strong absorption in the UV region; it possesses a robust colouring capability, significantly affecting the chromogenic results of the overglaze pigment. As the content of Fe2O3 is low, the ratio of Fe3+/Fe2+ is low, such as the absorption peak at P1 in sample MCH-2, then the absorption peak is narrower, presenting a yellow hue. With the increase in Fe2O3 content, the concentration of Fe3+ ions increases, the ratio of Fe3+/Fe2+ increases, and the aggregation effect on surrounding oxygen ions is enhanced, which increases the covalent bonding component in the Fe–O bond [49] and enhancing the coloring effect. It is manifested as the enhancement and broadening of the absorption peak at P1 in the absorption spectrum of overglaze yellow pigment, the wave to the visible region of the blue–violet spectrum and presents its complementary yellow colour, gradually increasing the colour (MZD-3, MWL-1). When the concentration of Fe3+ ions is excessively high, it can exceed the limit of the chemical reaction, causing the transformation of the tetrahedral [FeO4] coordination to octahedral [FeO6] coordination. This transformation facilitates the microcrystallization of glass, and in turn modifies the optical absorption behavior and chromogenic effect of the material. The octahedral [FeO6] coordination enters the interstitial positions outside the network. The overglaze yellow pigment indeed primarily exhibits its coloration through the d-d transition of the octahedral [FeO6] coordination. In the context of sample MJJ-1, this transition is evident at the absorption peak denoted as P2 in its absorption spectrum. The strong absorption at this peak, which spans both the ultraviolet and visible light regions, contributes to the pigment’s overall coloration. Specifically, in the visible light range, the blue-green region (P2’) is affected, leading the colorant to present its complementary yellow–brown colour [50].

Fig. 6
figure 6

Absorption spectrum of overglaze yellow pigments

Full size image

Furthermore, the effective electric field imposed by oxygen ions on the coloring ions is variable, and consequently, the cations near the oxygen polyhedron also influence the coordination field of the coloring ions. Taking the absorption peaks of sample MMD-4 as an example, as the PbO content increases, the amount of free oxygen also rises, which favors the maintenance of high-valent states of coloring ions. Due to the increase in the field strength of Pb2+, the effective electric field exerted by oxygen ions on the coloring metal ions decreases, thereby facilitating the formation of low-coordination [FeO4] by Fe3+ ions. This shift results in the absorption band moving towards longer wavelengths. Additionally, Pb2+ ions exhibit strong absorption in the near-ultraviolet region, which superimposes with the absorption effect of Fe3+ ions in the same region [51], enhancing the absorption peak of Fe3+ ions at P2 and broadening the absorption peak at P1, as observed in the absorption peaks of sample MMD-4. At this point, the overglaze yellow pigment is primarily attributed to the O2−-Fe3+ charge transfer of the tetrahedral [FeO4] coordination, leading to a deeper coloration.

In summary, the overglaze yellow pigment of Jingdezhen imperial kilns in the Ming dynasty is a result of the mixed coloring of Fe3+ and Fe2+ ions. Essentially, the coloration is dominated by a higher concentration of Fe3+ ions compared to Fe2+ ions, and the intensity of the coloration is closely related to the concentration of the coloring ions and their coordination field. In the Fe3+-O-Fe2+ structure, when the content of Fe3+ ions in the overglaze pigment is higher than that of Fe2+ ions, within a certain range, Fe2O3 can exist in the ionic state and primarily contribute to the coloration through the O2−-Fe3+ charge transfer of the tetrahedral [FeO4] coordination. As the concentration of Fe3+ increases or the tetrahedral coordination number rises, the coloration deepens. However, if the content of Fe3+ exceeds the limit of the chemical reaction, Fe2O3 coexists in both ionic and crystalline states, and the coloration shifts primarily to a yellow–brown hue through d-d transitions in [FeO6] coordination.

Conclusions

This study employed a range of micro-analytical techniques, including EDXRF, Raman analysis, XPS, and UV–vis analysis, to elucidate the chromogenic mechanisms of overglaze yellow pigment in porcelain samples from the Jingdezhen imperial kilns produced during the Ming dynasty. The results indicate that iron-based yellow was the only chromogenic agent for the overglaze yellow pigment in the Jingdezhen imperial kilns during the Ming dynasty. However, the content of both the alkali metal and coloring elements within the composition formula significantly influenced the coloration of the overglaze yellow pigment. The overglaze yellow pigment was primarily expressed through the Fe3+-O-Fe2+ structure, with Fe3+ ions modifying the hue. The intensity of the coloration was closely related to the concentration of coloring ions and the coordination field. Fe2O3 is fully integrated into the glaze matrix as iron ions within a specific range, and the overglaze yellow pigment primarily contributes to colour through the the O2−-Fe3+ charge transfer of the tetrahedral [FeO4] coordination. As the concentration of Fe3+ ions increased or the number of tetrahedral [FeO4] coordinations increased, the coloration became deeper. However, if the concentration of Fe3+ exceeds the limit of the chemical reaction, excess Fe2O3 appears in the crystalline form, altering the light absorption behavior. Fe3+ ions primarily induce colour changes through d-d transitions in the octahedral [FeO6] coordination, appearing as a yellow–brown colour. To our knowledge, this study provides scientific evidence for the first time for the connection between the internal structure and the appearance of the overglazed yellow pigment produced in Jingdezhen imperial kilns during the Ming dynasty in China.

Availability of data and materials

No datasets were generated or analysed during the current study.

Abbreviations

ED-XRF:

Energy dispersive X-ray fluorescence

RS:

Raman spectroscopy

XPS:

X-ray photoelectron spectroscopy

UV-vis-NIR:

Ultraviolet-visible-near infrared spectrophotometry

References

  1. Chen WL. Talk about the color of Chenghua kiln. Cult Relics. 1959;06:26–8 (in Chinese).

    Google Scholar 

  2. Kock LD. Raman spectroscopic studies of the underglaze pigments of porcelain shards of Archaeological origins [dissertation]. Pretoria: University of Pretoria; 2010.

    Google Scholar 

  3. Clark RJH, Cridland L, Benson M, Kariuki KDM, Harris DM, Withnall R. Synthesis, structural characterisation and Raman spectroscopy of the inorganic pigments lead tin yellow types I and II and lead antimonate yellow: their identification on medieval paintings and manuscripts. J Chem Soc. 1995:2577–2582.

  4. Zhang FK, Zhang ZG. Ancient Chinese overglaze colours. J Chin Ceramic Soc. 1980;04:339–50 (in Chinese).

    Google Scholar 

  5. Zhang ZG, Deng ZQ, Li JZ. Study on the doucai and polychrome in Chenghua period of the Ming Dynasty. In: Luo HJ, Zheng XM, editors. International Symposium on Ancient Ceramics-7, (ISAC’ 09). Shanghai: Shanghai Science and Technology Literature Press; 2009. p. 434–40 (in Chinese).

    Google Scholar 

  6. Chen SY. Micro-Raman analysis of Chenghua Doucai porcelain shards. J Natl Museum China. 2011;09:147–52 (in Chinese).

    Google Scholar 

  7. Zhao LW, Li QH, Dong JQ, et al. Scientific analyses of Ming Dynasty Doucai and Qing Dynasty famille-rose porcelain shards. Sci Conservation Archaeol. 2018;30(5):98–109 (in Chinese).

    Google Scholar 

  8. Wu J, Zhang ML, Wu JM. Raman and EDXRF study on overglaze pigments of Jingdezhen Ceramics. Spectrosc Spectral Anal. 2015;35(05):1266–70 (in Chinese).

    CAS  Google Scholar 

  9. He W, Xiong Y. A study of enamels on Chinese porcelain of Qing dynasty. In: Guo Jingkun, editor. Science and technology of ancient ceramics, 6: proceedings of the International Symposium (ISAC’05). Shanghai: Research Society of Science and Technology of Ancient Ceramics; 2005:446–451.

  10. Miao J, Yang B, Mu D. Identification and differentiation of opaque Chinese overglaze yellow enamels by Raman spectroscopy and supporting technique. Archaeometry. 2010;52(1):146–55.

    Article  CAS  Google Scholar 

  11. Kingery WD, Vandiver PB. The eighteenth-century change in technology and style from the famille verte to the famille rose style. In: Kingery WD, editor. Technology and style. Columbus: The American Ceramic Society; 1985. p. 363–81.

    Google Scholar 

  12. Colomban P, Ambrosi F, Ngo A, Lu T, Feng X, Chen S, Choi C. Comparative analysis of Wucai Chinese porcelains using mobile and fixed Raman microspectrometers. Ceram Int. 2017;43:14244–56.

    Article  CAS  Google Scholar 

  13. Colomban P, Zhang Y, Zhao B. Non-invasive Raman analyses of Chinese huafalang and related porcelain wares: searching for evidence for innovative pigment technologies. Ceram Int. 2017;43:12079–88.

    Article  CAS  Google Scholar 

  14. Kerr R, Wood N. Science and civilisation in China, 5: XII: Ceramic Technology. Cambridge: Cambridge University Press; 2004. p. 616.

    Google Scholar 

  15. Dentrecolles FX. The First Letter from Père d’Entrecolles to Father Orry (Raozhou, 1712). In: Tichane R, Nilsson JE, translators. Gotheborg; 2010.

  16. Dentrecolles FX. The Second Letter from Father d’Entrecolles to Father Orry (Jingdezhen, 1722). In: Tichane R, Nilsson JE, translators. Gotheborg; 2010.

  17. Ebelmen JJ, Salvétat LA. Sur la composition des matières employées dans la fabrication et dans la décoration de la porcelaine en Chine. Annales de Chimie et de Physique. 1852;3é Série; XXXV:312–365.

  18. Jiang JX. Song, Yuan and early Ming Dynasty glazed colored porcelain. Beijing: Science Press; 2013. (in Chinese).

    Google Scholar 

  19. Jiang XM. On the painting techniques for Ming Chenghua Doucai porcelains by archaeological materials. Palace Museum J. 2016;02:44–53 (in Chinese).

    Google Scholar 

  20. Hao PY. The evolution of Wucai porcelain in Ming and Qing Dynasties. Cultural Relics World. 2015;07:73–7 (in Chinese).

    Google Scholar 

  21. Eppler R, Eppler DR. Glazes and glass coatings. Westerville: American Ceramic Society; 2000.

    Google Scholar 

  22. Colomban P. Full spectral range raman signatures related to changes in Enameling technologies from the 18th to the 20th Century: guidelines, effectiveness and limitations of the Raman analysis. Materials. 2022;15:3158.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Wang XD. Effects of different metal ions and adsorbed water on turquoise colour [dissertation]. Beijing: China University of Geosciences; 2021. (in Chinese).

    Google Scholar 

  24. Van Grieken RE, Markowicz AA, editors. Handbook of X-ray spectrometry. 2nd ed. New York: Marcel Dekker; 2002.

    Google Scholar 

  25. Arli BD, Franci GS, Kaya S, et al. Portable X-ray fluorescence (p-XRF) uncertainty estimation for glazed ceramic analysis: case of Iznik Tiles. Heritage. 2020;3(72):1302.

    Article  Google Scholar 

  26. Bersani D, et al. Micro-Raman investigation of iron oxide films and powders produced by sol-gel syntheses. J Raman Spectrosc. 1999;30(5):335–60.

    Article  Google Scholar 

  27. de Faria DLA, Lopes FN. Heated goethite and natural hematite: can Raman spectroscopy be used to differentiate them? Vib Spectrosc. 2007;45:117–21.

    Article  Google Scholar 

  28. Wang ZM. Jiangxi Dazhi. Hong Kong: Cheng Wen Publishing Company; 1989. (in Chinese).

    Google Scholar 

  29. Zhou GX. X-ray diffraction analysis of ancient mural pigments. In: Wang JR, editor. A century of Dunhuang studies in China. Gansu: Gansu Culture Publishing House; 1999. p. 61–8 (in Chinese).

    Google Scholar 

  30. Kajihara S, Hidaka M, Wijesundera R, et al. Correlation between the Izumiyama Porcelain Ceramics and the Red-overglaze Enamels of the Kakiemon-style Porcelains. Ceram Int. 2008;34(7):1681–9.

    Article  CAS  Google Scholar 

  31. Kirmizi B, Colomban P, Quette B. On-site analysis of Chinese Cloisonné enamels from fifteenth to nineteenth centuries. J Raman Spectrosc. 2010;41:780–90.

    Article  CAS  Google Scholar 

  32. Colomban P, Tournié A, Bellot-Gurlet L. Raman identification of glassy silicates used in ceramic, glass and jewellery: a tentative differentiation guide. J Raman Spectrosc. 2006;37:841–52.

    Article  CAS  Google Scholar 

  33. You JL, Jiang GC, Hou HY, et al. Quantum chemistry study on superstructure and Raman spectra of binary sodium silicates. J Raman Spectrosc. 2004;36(3):237–49.

    Article  Google Scholar 

  34. Labet V, Colomban P. Vibrational properties of silicates: a cluster model able to reproduce the effect of “SiO4” polymerization on Raman intensities. J Non-Crystall Solids. 2013;370:10–7.

    Article  CAS  Google Scholar 

  35. Colomban P. Polymerization degree and Raman identification of ancient glasses used for jewelry, ceramic enamels and mosaics. J Non-Cryst Solids. 2003;323:180–7.

    Article  CAS  Google Scholar 

  36. Colomban P, Paulsen O. Raman determination of the structure and composition of glazes. J Am Ceram Soc. 2005;88:390–5.

    Article  CAS  Google Scholar 

  37. Colomban P. Glaze and enamels. In: Richet P, editor. Encyclopedia of Glass science, technology, history and culture. 1st ed. Hoboken: John Wiley & Sons; 2020. p. 1309–26.

    Google Scholar 

  38. Xu PC, Li RB, et al. Raman spectroscopy in geology. Xi’an: Shanxi Science and Technology Press; 1996. p. 46–51.

    Google Scholar 

  39. Colomban P, Gironda M, Simsek Franci G, d’Abrigeon P. Distinguishing genuine imperial Qing dynasty porcelain from ancient replicas by on-site non-invasive XRF and Raman spectroscopy. Materials. 2022;15(16):5747.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Bouchard M, Smith DC. Catalogue of 45 reference Raman spectra of minerals concerning research in art history or archaeology, especially on corroded metals and coloured glass. Spectrochim Acta Part A Mol Biomol Spectrosc. 2003;59:2247–66.

    Article  CAS  Google Scholar 

  41. Cvejic Z, Rakic S, Kremenovic A, Antic B, Jovalekic C, Colomban P. Nanosize ferrites obtained by ball milling: crystal structure, cation distribution, size-strain analysis and Raman investigations. Solid State Sci. 2006;8:908–15.

    Article  CAS  Google Scholar 

  42. Simsek G, Geckinli AE. An assessment study of tiles from Topkapı Palace Museum with energy-dispersive X-ray and Raman spectrometers. J Raman Spectrosc. 2012;43(7):917–27.

    Article  CAS  Google Scholar 

  43. Yamashita T, Hayes P. Analysis of XPS spectra of Fe2⁺ and Fe3⁺ ions in oxide materials. Appl Surf Sci. 2008;254(8):2441–9.

    Article  CAS  Google Scholar 

  44. Ke YK, Dong HR. Handbook of modern chemistry. Beijing: Chemical Industry Press; 2015. p. 8.

    Google Scholar 

  45. Shi P, Wang F, Zhu J, et al. Effect of phase separation on the Jian ware blue colored glaze with iron oxide. Ceram Int. 2018;44(14):16407–13 (in Chinese).

    Article  CAS  Google Scholar 

  46. Weyl WA. Coloured glasses. London: The Society of Glass Technology; 1999.

    Google Scholar 

  47. Chen F, Wu LH, Zhao EL. Introduction to color glass. Beijing: Chemical Industry Press; 2009. p. 163–6.

    Google Scholar 

  48. Zhang CW. Structural analysis and ligand field theory of iron colouring in glass. Glass and Enamelling. 2004;6:39–42 (in Chinese).

    Google Scholar 

  49. Xia YF, Liu RC, Wang SX, Xu C, Pan SY, Cheng YB. A study of the oxygen-collecting effect of iron ions in glass. Acta Physica Sinica. 1985;34:259–62 (in Chinese).

    Article  CAS  Google Scholar 

  50. Ning YC. Organic wave spectroscopy spectral analysis. Beijign: Science Press; 2016. (in Chinese).

    Google Scholar 

  51. Wang F, Miao JM, Hou JY, Lin Y, Zhu JF. Colour rendering of iron oxides in the sky-blue and sky-cyan glazes of Jun porcelain. J Palace Museum. 2012;3:100–8 (in Chinese).

    Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

This research was financially supported by National Social Science Foundation of China (22VJXG025).

Author information

Authors and Affiliations

  1. School of Archaeology and Museology, University of Jingdezhen Ceramic, Jingdezhen, 333403, China

    Meng Hao & Maolin Zhang

  2. Institute of Jingdezhen Imperial Kiln, Jingdezhen, 333000, China

    Yanjun Weng & Zhe Xiong

Authors
  1. Meng Hao
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Maolin Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Yanjun Weng
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Zhe Xiong
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

M.Z. provided support and guidance for this study; M.H. performed all the experiments test, interpreted the data and wrote the manuscript; Y.W. and Z.X. provided some of the samples. All authors read and approved the final manuscript.

Corresponding authors

Correspondence to Maolin Zhang or Yanjun Weng.

Ethics declarations

Ethics approval and consent participate

Not applicable.

Competing interests

The authors declare no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Hao, M., Zhang, M., Weng, Y. et al. Chromogenic mechanisms of overglaze yellow pigment produced in Jingdezhen imperial kilns during the Ming dynasty. Herit Sci 12, 343 (2024). https://doi.org/10.1186/s40494-024-01458-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s40494-024-01458-0

Keywords