Natural Dyes Research Articles

Dyeing of Silk Yarn With Natural Dye from Teak Leaves

Objective: This study investigated the impacts of using teak leaf-derived natural dye for dyeing silk yarn. Theoretical Framework: This research uses a conceptual framework for the development of natural fibers for application in textile production. By testing the properties of dyed fibers obtained from teak trees cultivated in Thailand. which tests the properties of the fibers and the adhesion of colors obtained from teak trees. Method: This research explored two mordanting methods (pre-mordanting and post-mordanting) across varying conditions. The study documented the ideal parameters for dyeing, as well as color values, color strength, and fastness properties of the silk yarn. Results and Discussion: by dyeing at 90°C for 60 minutes with a pH of 3. Silk yarn treated with a mixture of teak leaf extract and a mordant substance displayed a yellowish-brown color, except when dyed with ferrous sulfate, which produced a dark gray-brown shade. The silk yarn exhibited fair color fastness when subjected to washing and perspiration, while its resistance to light was rated as poor–moderate. On the other hand, the results in terms of rubbing and water fastness showed a good to very good level. Research Implications: The fibers obtained from the research process have the properties of fibers and color adhesion on the yarn that are highly resistant to washing. Moreover, dyed yarn is beautiful and durable. Originality/Value: These findings underscore the potential utility of teak leaf extract-based natural dyes for silk yarn dyeing.

Design engineering of photoanode and counter electrode using lanthanum titanate infused natural dyes and activated carbon to enhance the performance of dye sensitized solar cells

Perovskite material of LaTiO3 has been synthesized by sol-gel technique and coated over TiO2 coated FTO substrate. Soxhlet extractor is used to extract the natural dyes from Cordyline Fruticosa and Clitoria Ternatea and perovskite material incorporated TiO2/FTO substrate is immersed in the dye solution to serve as photoanode material. The mixture of dye and perovskite material/TiO2 is characterized by UV–Visible, FTIR, XRD, SEM and Raman spectroscopy. The activated carbon prepared from coconut shell is served as counter electrode and sandwiched with Photoanode and electrolyte (I−/I3−) Redox couple to obtain the solar cell. The fabricated solar cells are subjected to JV characteristics and it is found that the cell with dyes from Cordyline Fruticosa with Perovskite/TiO2 has given highest efficiency of 0.494 % due to the rapid charge transfer from the dye to the semiconductor oxide material with decreased recombination of electrolyte.

Chromaticity of Gromwell, Cape jasmine Dyeing, and Effects of Zinc Oxide/Polyphenol Treatment with Copper Mordanting for UV Protection

To protect skin from harmful ultraviolet (UV) radiation, there has been a resurgence in the use of natural dyes with metal mordants to reduce contamination by advanced chemicals. This study achieved natural dyeing in violet and yellow colors from Gromwell red roots and Cape jasmine seeds for UV-protective materials. The dyed fabrics were subjected to zinc oxide (ZnO) and polyphenol treatments, as well as copper post-mordanting. The SEM, TEM, and XRD tests showed that the ZnO nanoparticles, with hexagonal crystal structures, stuck to the fiber surfaces, and twisted strands resulted in the K/S reduction. First, this study found that the untreated cotton in violet, despite the highest K/S, faded the most intensely when exposed to UV. The color variation of untreated polyester was narrow, with little change in L, a*, and K/S. The color change of yellow-dyed samples treated with ZnO/polyphenol was not considerable in yellowness (b*: 28.838), while the violet fabrics displayed a significant decrease in K/S and an increase in b*. The combination of ZnO and polyphenol treatment improved UV absorption at 350 to 250 nm. Among the Cu-mordanted fabrics after ZnO/phenols treatment, the violet cotton turned reddish from blueish (negative to positive b*), with a hue change of 316° to 59° and the highest ΔE (25.90 ± 4.34) after UV exposure. In this study, the combination of ZnO/polyphenol with Cu-mordants allowed the Cape jasmine-dyed polyester to achieve a minimum ΔE as well as to keep its chroma and hue after UV exposure.

Enhancing the stability of DSSC by Co-activation of microwave synthesized TiO2 with biomass derived carbon dots

Dye-sensitized solar cells (DSSCs) that utilize natural dyes have garnered interest due to their low cost, eco-friendly manufacturing process, and competitive photovoltaic performance. However, their efficiency and stability issues have hindered their widespread implementation. To enhance their performance, this paper proposes a novel approach of modifying the photoanode with carbon dots (CDs) to align the band gap for easier carrier collection. The material properties were thoroughly characterized by examining their structural, morphological, optical, and electrical properties. In this study, titanium dioxide (TiO2) was synthesized using the microwave-assisted solvothermal method, while nitrogen-doped CDs derived from Citrus medica fruit juice were prepared using a simple hydrothermal treatment. Three sets of Natural Dye Sensitized Solar Cells (NDSSC) devices were created using co-activated photoanode (CD/TiO2) and unmodified photoanode (TiO2) with Platisol T/sp coated ITO serving as the counter electrode. Hibiscus (Hibiscus rosa-sinensis) and Onion (Allium cepa) peel extracts were utilized as sensitizers and Iodolyte HI-30 as the electrolyte. The most efficient device attained an efficiency of 3.5 % with Voc = 0.81 V and Jsc = 6.57 mA/cm2. This marks the highest efficiency reported using Hibiscus as a sensitizer with the current configuration, accompanied by prolonged device stability. This study showcases the potential of Citrus medica-derived nitrogen-doped CDs in achieving durable device stability.

Utilization of Waste Banana Peels and Corn Cobs as Substrates in Neurospora sitophila Fermentation for Production of Natural Yellow Dyes

In the current situation, biomass gasification has become a major interest in producing clean energy and green chemicals. By gasification, the biomass can be converted to synthetic gas (syngas) for many purposes. However, syngas with high tar content can cause pipeline fouling and disturb the operation of downstream equipment. To reduce tar content, a two-series wet scrubber was installed for syngas cleaning produced by palm kernel shell gasification. Firstly, the gasification is operated at a temperature range of 500 – 600oC and 700 – 800oC to determine the conditions where the lowest tar syngas is produced. After that, the wet scrubber is installed with a variety of solvents including isopropyl alcohol, water, used cooking oil, and used lubricating oil. The results show that the lowest tar syngas was produced at a temperature of 800oC with a tar yield of 0.165 g/kg biomass. Meanwhile, in the same condition, isopropyl alcohol delivers the most substantial impact on tar removal efficiency, whereas used lubricating oil results in less impact. The use of isopropyl alcohol resulted in 99.25% tar removal effectiveness while lubricating oil yielded just 50.32%.

NATURAL DYEING OF COTTON FABRIC EXTRACTED FROM ROSA (ROSE) AND GENUS TAGETS (MARIGOLD) FLOWERS

In this study, the natural dye from rosa and genus taget flower is extracted through aqueous, alkaline and acidic extraction method and applied on cotton fabric and then evaluated its results. For dye extraction, petals of red rose was boiled and then filter the solution and decolorized petals were taken out of it. By using AATTC 61 dyeing method dye was applied on fabric in Industry. In aqueous, acidic and alkaline extraction same method used. In acidic extraction acidic acid and alkaline extraction sodium hydroxide was used. After applying natural dye on cotton fabric evaluated its result through colourfastness to wash and colourfastness to light tests. In colourfastness to wash the shade change and staining was measured through washing procedure. In colourfastness to light the shade change was measured through light procedure four readings were taken and mean was calculated. The result were interpreted in tables and graphs by using SPSS. In both test dyes from acidic extraction gives best results.

Effect of Antigonon leptopus extract in corn starch-glycerol based film as colourimetric indicator film for monitoring fish freshness

A colourimetric indicator can be used to test the freshness of fish in a rapid, straightforward and non-destructive manner. Anthocyanin, a natural dye found in Antigonon leptopus flowers, has a sensitive colour reactivity to a wide range of pH levels and can be made into colourimetric indicator films on a laboratory scale, making it a viable replacement for artificial dyes. The study's purpose was to see how the concentration of A. leptopus extract affected the colourimetric assessment of fish freshness. Ethanol was used to extract anthocyanin from A. leptopus. FTIR and pHrespond spectroscopies were used to characterise the extracts. Colourimetric indicator films were developed to assess fish freshness by incorporating A. leptopus extract into a corn starch-glycerol matrix via the solution casting method, with concentrations of 10%, 30% and 50%, respectively. The effect of A. leptopus extract on visual aspects, thickness, morphology, FTIR spectra, UV-Vis spectra and colour responses was analysed. Microbial analysis, TVB-N contents, firmness, and pH of the fish samples were analysed after storage. The colour of the original films became darker as the extracted content increased. There was no significant (p>0.05) effect of A. leptopus extract on film thickness. SEM micrographs revealed that the composite films had homogeneous and whitish granules on the surface and that increasing the A. leptopus extract concentration caused the films to become rougher. FTIR and UV-Vis spectroscopies showed successful binding between A. leptopus extracts and corn starch-glycerol film. With increasing pH, the colour change of the films exposed to pH = 3-11 solutions was no significant difference due to improper storage. An increase in the microbial population, TVB-N content and pH was observed over the storage period as a result of fish deterioration. Colour changes were also identified in the film which became darker. Overall, colourimetric indicator film with 50% A. leptopus extract was found to be the optimal formulation since it had the highest values in ∆E* during progressive spoilage of fish.

Exploring the Potential of Dacryodes Edulis Leaf Extract as Natural Colourant on Polyamide Fabrics: Extraction, Characterization and Application

There is a growing demand for sustainable and eco-friendly alternatives in the textile industry, particularly in search of natural colourants derived from plants. This research study investigates the extraction and characterization of natural colourant from the leaf of D. edulis and explores its application to polyamide fabrics. Laboratory experiments, such as solvent extraction was performed to obtain the colourant. The extraction process was optimized using Response Surface Methodology-Central Composite Design (RSM). The dye was isolated and characterized using vacuum liquid chromatography, UV-Vis spectrophotometry, high-performance liquid chromatography and Fourier-transform infrared spectroscopy. Physical properties such as light fastness, perspiration fastness, rubbing fastness and wash fastness were assessed to determine the durability and stability of the natural colourant on the fabrics. The results indicated that the optimal conditions for dye extraction are 65.9 ℃ and 2 hours, providing feasible parameters for replication. Examination of the natural dye obtained from the isolated fraction, revealed the presence of carbon-carbon double bonds (C=C), carbonyl (C=O), ester (-COO), aldehyde (CHO) and hydroxyl (-OH) groups; with rutin, isoquercetin and tannic acid as its major compounds. The isolated dye exhibited an absorption peak at 403 nm. The ratings for the treated fabrics varied from fair to good and very good. The light fastness ranged from 4 to 6, perspiration fastness and wash fastness ranged from 2-4, and rubbing fastness ranged from 3-5. On the other hand, the untreated fabrics had ratings, with a range of 2-5 for light fastness, 2-4 for perspiration fastness and wash fastness and 1-4 for rubbing fastness, it was also observed that the colour strength values of mordanted fabrics were deeper than those of the unmordanted fabrics. These results indicate that the dye obtained from D. edulis leaf has considerable potential as a source of natural dyes. These findings contribute valuable insights into the extraction, characterization and application of natural colourants, promoting a shift towards more sustainable and eco-friendly practices in the textile industry.

Development of a Sensitive Colorimetric Indicator for Detecting Beef Spoilage in Smart Packaging.

This study aimed to fabricate and characterize a novel colorimetric indicator designed to detect ammonia (NH3) and monitor meat freshness. The sensing platform was constructed using electrospun nanofibers made from polylactic acid (PLA), which were then impregnated with anthocyanins as a natural pH-sensitive dye, extracted from red cabbage. This research involved investigating the relationship between the various concentrations of anthocyanins and the colorimetric platform's efficiency when exposed to ammonia vapor. Scanning electron microscope (SEM) results were used to examine the morphology and structure of the nanofiber mats before and after the dip-coating process. The study also delved into the selectivity of the indicator when exposed to various volatile organic compounds (VOCs) and their stability under extreme humidity levels. Furthermore, the platform's sensitivity was evaluated as it encountered ammonia (NH3) in concentrations ranging from 1 to 100 ppm, with varying dye concentrations. The developed indicator demonstrated an exceptional detection limit of 1 ppm of MH3 within just 30 min, making it highly sensitive to subtle changes in gas concentration. The indicator proved effective in assessing meat freshness by detecting spoilage levels in beef over time. It reliably identified spoilage after 10 h and 7 days, corresponding to bacterial growth thresholds (107 CFU/mL), both at room temperature and in refrigerated environments, respectively. With its simple visual detection mechanism, the platform offered a straightforward and user-friendly solution for consumers and industry professionals alike to monitor packaged beef freshness, enhancing food safety and quality assurance.

Enhancing Efficiency of Dye Sensitized Solar Cells by Coinage Metal Doping of Cyanidin-Silver Trimer Hybrids at TiO2 Support Based on Theoretical Study.

Identification of a natural-based sensitizer with optimal stability and efficiency for dye-sensitized solar cell (DSSC) application remains a challenging task. Previously, we proposed a new class of sensitizers based on bio-nano hybrids. These systems composed of natural cyanidin dyes interacting with silver nanoclusters (NCs) have demonstrated enhanced opto-electronic and photovoltaic properties. In this study, we explore the doping of silver nanocluster within a cyanidin-Ag3 hybrid employing Density Functional Theory (DFT) and its time-dependent counterpart (TDDFT). Specifically, we investigate the influence of coinage metal atoms (Au and Cu) on the properties of the cyanidin-Ag3 system. Our findings suggest that cyanidin-Ag2Au and cyanidin-AgAuCu emerge as the most promising candidates for improved light harvesting efficiency, increased two-photon absorption, and strong coupling to the TiO2 surface. These theoretical predictions suggest the viability of replacing larger silver NCs with heterometallic trimers such as Ag2Au or AgAuCu, presenting new avenues for utilizing bio-nano hybrids at the surface for DSSC application.

A PEWARNA ALAMI AKAR MENGKUDU (Morinda citrifolia L) SEBAGAI PENGGANTI SAFRANIN PADA PEWARNAAN GRAM NEGATIF

Noni is a plant that has the potential to be used as a therapeutic element, but many people are still unaware of its benefits. This plant is one of the herbal plants part of the noni plant has body parts that can almost all be utilised. Noni root or known as Morinda citrifolia L. can be processed and used as a natural dye because it contains morindon. Noni contains the molecule morindin, a disaccharide derivative of anthraquinone or anthraquinone, so its roots are used as a dye. Morindon is a natural dye produced when morindin glycoside is hydrolysed which will produce a red colour. Morinda citrifolia Linn fruit has antibacterial properties inherent in phenol and flavonoid molecules. The purpose of this study is to determine whether or not noni root extract can be used as an alternative to safranin gram staining. The variables used were noni root extract and gram staining which were carried out by Experimental Laboratories. This research began in May to June 2023. The results showed that noni root extract in a 60-second soak could colour gram-negative bacteria but in 20-second and 30-second soaks there was no red colour on gram-negative bacteria. Noni root extract can be applied as an alternative gram stain to safranin.

Pemanfaatan Perasan Daun Pacar Air (impatins balsamina) Sebagai Alternatif Pewarnaan Alami Pengganti Eosin 2% Pada Pemeriksaan Telur Cacing Ascaris lumbricoides

The leaves of the water henna plant (Impatien balsamina L.) contain anthocyanins. Natural dyes with an orange-reddish-brown colour are made from compounds called anthocyanins. Knowing whether the leaves of Impatiens balsamina L. can be used as a dye substitute for worm eggs is the purpose of this study. To distinguish the background contrast and make the shape and components of the worm eggs clearer, 2% eosin reagent dye was added during the testing process. Eosin 2% will produce a red color in the background of the preparation field of view .This study used an experimental method on 3 different treatment variations based on the concentration of water henna leaves (Impatients balsamina L) using distilled water in a brown bottle 20%, 10%, 5%. The results illustrate the variation of Impatients balsamina L. leaf concentration, 20%, 10%, and 5% used as an alternative dye in examining worm eggs. For each treatment modification, there was an apparent but not statistically significant variation in staining quality. The staining effect of water henna leaf juice, produces a contrasting background, allowing the dye to be absorbed by the egg, and highlighting the shape and components of the egg. In the experimental preparations, alternative staining was carried out using squeezed water and looking at the comparison of each concentration.

Strategizing Sustainable Style: Examining Green Marketing for Natural Dye Batik in Indonesia

Strategizing Sustainable Style: Examining Green Marketing for Natural Dye Batik in Indonesia

Natural Dyes in Embroideries of Byzantine Tradition, the Collection of Embroidered Aëres and Epitaphioi in the National Museum of Art of Romania

The medieval textiles collection of the National Museum of Art of Romania (MNAR) has been in place since 1865 and nowadays preserves about 1000 medieval and pre-modern weavings and embroideries. These extremely valuable objects, dated between the 14th and the 19th centuries, are mainly religious embroidered garments and veils with special significance in the Byzantine li-turgy. Ecclesiastical embroideries of Byzantine tradition are characterized by a complex technique: metallic threads with a silk core, metallic wires and coloured silk threads are couched over padding on layers of silk and cellulosic supports so as to create relief through light reflection. The silk sup-ports and the sewing threads are coloured, mainly in red, blue, green and yellow hues, and analytical investigations of the dyes used in embroideries preserved in the MNAR, in the Putna and Sucevița Monasteries, have been released in previous studies by the corresponding author. The present work continues the approach with research into dyes in about 25 aëres and epitaphioi from the MNAR collection. Considering their privileged function in the liturgical ritual, these luxurious pieces embroidered with silver, gilded silver or coloured silk threads and decorated with pearls, sequins or semi-precious stones are the most faithful description of the stylistic and technological evolution of the art of post-Byzantine embroidery in the Romanian provinces. The data resulting from the present research will improve the knowledge regarding this topic. Dye analysis was performed by liquid chromatography with diode array detection, while fibres were characterized by infrared spectroscopy (with attenuated total reflectance) and optical microscopy. The biological sources identified—carminic acid-based dyes, redwood, dyer’s broom, weld, indigo-based dyes––will be discussed in correspondence with their use in the embroidery technique: support, lining and embroidery threads, together with other sources previously reported on Byzantine embroideries in Romanian collections, and in similar objects preserved at Holy Mount Athos.

Fast prediction of optimal reaction conditions and dyeing effects of natural dyes on silk fabrics by lightweight integrated learning (XGBoost) models

AbstractThere is a lot of repetitive work involved in exploring the dyeing performance of natural dyes. To improve the experimental efficiency, save material, reduce time costs and shorten the research cycle, this study collects and analyses the literature data of 350 natural dye experiments to construct the Natural Dyes Dataset, and achieves rapid prediction of the optimal reaction conditions and dyeing effects of natural dyes using a lightweight integrated learning model. The size of the trained XGBoost model is only 562 KB; only the name of the dye and its approximate chemical composition need to be input to predict the results of the reaction environment pH, colour fastness to washing (CFW) and colour fastness to rubbing (CFR) of the natural dye on silk fabrics with the highest K/S in a very short time of 52 ms. The prediction accuracies for pH, CFW and CFR in the validation set are as high as 94.12%, 93.75% and 100%, respectively, and 77.78%, 91.67% and 83.33% for the real test set, with both validity and transferability. The integrated learning approach provides valuable guidance for exploring the dyeing performance of natural dyes with very small deployment costs and a very short inference time, expanding the possibilities of cross‐application of the disciplines of machine learning and textile dyeing.

DESIGNING OF UV PROTECTIVE CLOTHING FOR KIDS

The most secure protection against ultraviolet (UV) radiation exposure is offered by textiles, such as different kinds of apparel, caps, and umbrellas. Clothing is the most effective way to protect against UV radiation (UVR) exposure. Different fabrics have different levels of dyeing with natural, synthetic or artificial fibres depending on their properties. While reviewing, the researcher found that some natural dyes are in appealing colours which have UV-protective properties and obtained excellent results. The creation of these natural colours was done by utilizing fruit peel, plant-based dyes, vegetable dyes, dry fruits, and pulses. Other researchers investigated these natural hues. Researcher is utilizing these findings to create UV-protective clothing by using a wide range of natural colours. There are several companies in the market which provide UV protective clothing using artificial colours but they don’t use any designing element for kids wear. Skin of kids is more delicate; therefore, they require special attention and protection from the sun. The objective of this study is to produce designer and protective clothing with natural dye that have the necessary UV protection. Five different tie-dye techniques were used in this study to develop clothing that protects young girls from UV rays. By examining their structural, aesthetic, and functional aspects, it was determined that protective clothing designs were accepted by the mothers and their caretakers.

Sustainable scouring of cotton using extracts from wood ash and soapnut and its optimisation by response surface methodology

AbstractThe non‐cellulosic impurities like oil, wax, and pectins present in the cotton fibre adversely impact wetting. Consequently, these impurities must be removed during the pretreatment process to prevent unevenness of subsequent coloration. Generally, an alkaline treatment with petroleum‐based synthetic surfactants is done, which is called scouring. This study attempts to develop an environmentally safe alternative using alkali from wood ash extract (WAE) and surfactant from soapnut extract (SE). The factors of WAE (10%–30%), SE (5–15 g/L), temperature (75–95°C), and time (20–60 min) were optimised using response surface methodology. A concentration of 20% WAE and 10 g/L SE at 90°C for 30 min was found to be adequate to remove impurities. The statistically optimised method showed good hydrophilicity, indicated by an average wetting time of 15 s, and 2.7% weight loss. The scoured fabric was subsequently dyed with natural dye extracted from marigold flowers and reactive dye. The scoured cotton was evaluated by weight loss, wettability, tensile strength, whiteness index, and colour value (K/S) and showed comparable results to conventional scouring.

HASIL PEMERIKSAAN TELUR SOIL TRANSMITTED HELMINTH MENGGUNAKAN CAMPURAN PEWARNA ALAMI DARI DAUN MIANA DAN KULIT BUAH NAGA

The simplest method for checking worm eggs is by a native technique using a 2% eosin reagent. Eosin itself has properties that are not easily decomposed, causing hazardous and easily flammable waste. Hence, an alternative staining method is needed, environmentally friendly, using natural materials, such as natural dye substances. This research aims to understand the depiction of results in examining Soil Transmitted Helminth (STH) eggs using mint leaves and dragon fruit skin as alternative reagents. The research method involves examining feces using a direct method (wet preparation) to detect worm eggs in feces directly using a 2% Eosin solution. The comparison results between dragon fruit peel extract concentration using aquadest, tested with SPSS analysis version 20 using the Kruskal-Wallis method with a significance value of 0.09 ≥ 0.05, indicating significantly different research outcomes. Thus, it can be concluded that there is no difference in staining quality compared to the control. The conclusion drawn from this study is that there's no difference in staining worm egg suspensions using mint leaf extract. This is evident as when observing the worm egg suspension using mint leaf extract, the worm eggs were not clearer, unlike with dragon fruit skin and miana.

Enhancing the efficiency of hemp fiber dyeing with natural dyes: Indigo and lac

Hemp fibers dyed with natural dyes are environmentally sustainable, but it is typically difficult to achieve an intense shade and washing durability. In this study, mercerization and cationization using polyelectrolyte, Poly-diallyldimethylammonium chloride (polyDADMAC), were chosen to enhance the dyeing efficiency and mechanical properties. Indigo and lac were chosen as natural dyes due to their widespread use. SEM demonstrated that untreated fibers contained the non-cellulose boundary layer on the surfaces, but after mercerization, the surfaces were smoother, making them suitable for absorbing natural dyes. In agreement with the FT-IR, the spectra of non-cellulose disappeared after mercerizing. Following cationization, the FT-IR spectra confirmed the consequences of using poly-DADMAC. Tensile testing demonstrated that mercerized hemp yarns were 34.1% stronger compared to untreated hemp yarns due to the decrease in non-cellulose content and that the intermolecular attraction of cellulose was not disturbed. The color strength and fastness properties were described by the K/S value. Mercerization considerably affected the K/S of indigo dyeing, while cationization affected lac dyeing significantly. Besides that, both treatments improved fastness properties as well.

Revealing the Dye Components in 1250-Year-Old Japanese Textiles Via High-Performance Liquid Chromatography

ABSTRACT Since the mid-eighth century, Shosoin textiles have been continuously handed down in the Shosoin treasure repository of the Todaiji temple, Japan, and the brilliant colors of these ancient textiles have been maintained in good condition thus far. In this study, the chemical stabilities of madders (Rubia akane and R. tinctorum), gromwell (Lithospermum erythrorhizon), and blue indigo dyes remaining in the textiles passed down for more than 1250 years were examined. The dye components remaining in the silk or wool textiles were analyzed by high-performance liquid chromatography equipped with a photodiode array detector. Chromatograms of the extracts from the textiles revealed not only the principal chromophores of the dyes but also 6-hydroxyrubiadin glycosides and shikonin esters in Japanese madder and gromwell, respectively. These results indicated that the chromophore skeletons, glycoside linkages, and ester linkages of the dye components were retained for more than 1250 years after the textiles were stored in the treasure repository. These findings of the chemical stability and the ongoing degradation of ancient natural dyes help in preserving the dye components and slowing down their degradation.