Search Results (14)

A small dyer’s handbook in Dr. Georg Kremer’s archive presents unexpected challenges. The handwritten recipes can be dated back to the early 19th century. The author must have been an experienced dyer, who wrote down detailed instructions for dyeing or printing on cotton, wool and silk. More than 80 dyed textile samples were sewn or glued into the book. A colourful palette is achieved with natural dyes such as indigo, cochineal, madder, alkanna, annatto, turmeric and quercitron. Furthermore, inorganic pigments like Prussian blue and chrome yellow were used. Unfortunately, the text is characterized by regional accent and inconsistent spelling. Language analysis was able to assign the origin of the author to the Vogtland, a region in Germany that covers parts of Bavaria, Thuringia and Saxony. The spelling or misspelling of the words may leave readers with a smile, but also make it difficult to figure out ingredients, chemicals or dyes. The measurement units given in the recipes are problematic. Additionally, vessels of vague volumes such as hand buckets or coffee cups are used. In this study, the content of the notebook is evaluated, and initial reproductions are carried out to find out how useful these recipes are for further research. Full article

The Royal Textile Factory of Covilhã, founded in 1764, is the perfect example of the Portuguese Industrial and Cultural Heritage. Despite its historical significance, comprehensive studies on the dyeing techniques employed in the 18th century remain scarce. Given the influence of French technology on Portuguese wool production, this study presents a comparative analysis of French and Spanish dyeing recipes to understand their influence on the practices adopted by the Portuguese wool industry. Focusing on the production of red dyes from cochineal insects, one of the main colours used in Covilhã until the late 19th century, this work presents the reconstruction of selected 18th-century scarlet recipes. Quantitative and qualitative differences between French and Spanish methodologies were analysed, particularly regarding the use of mordants, the quantities of cochineal, and the role of pH and tin liquor in achieving scarlet shades. The results highlight that although both traditions relied heavily on cochineal, significant variations existed in recipe composition and application. This work contributes to a better understanding of historical dyeing techniques and supports future conservation and reproduction efforts for Portuguese textile heritage. Full article

Food colourants are widely used additives classified as either synthetic or natural. In recent years, consumers have increasingly favoured natural options, considering them safer and potentially beneficial due to their nutritional properties. This study examined the effects of a natural food colourant, commercially known as Vegan Red (RVEG), on zebrafish embryonic development. Its impact was compared with cochineal red E120, of animal origin, and the synthetic dye E124, which are associated with hyperactivity in children and allergies. Shield stage embryos were exposed for 72 h and then examined using a multidisciplinary approach to assess the effects on conventional toxicity endpoints, such as survival, hatching rate, heart rate, genotoxicity, and behavioural interferences, including the impact on muscle ultrastructure. The results demonstrated that RVEG, as well as E120, do not affect hatching, heart rate, and motility parameters. However, RVEG moderately alters skeletal muscle organisation and, more relevant, the expression of the gfap, chchd2, and notch1a genes. Based on standard toxicity parameters, the findings indicated that RVEG is less toxic than E124 and E120, but that the alterations induced in gene expression and muscle anatomy raise safety concerns. Full article

The dyes used to produce two Palestinian garments from the British Museum’s collection attributed to the late 19th–early 20th century were investigated by high pressure liquid chromatography coupled with diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS). Palestinian embroidery is a symbol of national identity and the topic of scholarly research. However, little attention has been given to the dyes and how these changed with the introduction of new synthetic formulations in the second half of the 19th century. The results revealed the use of natural indigoid blue and red madder (Rubia tinctorum), in combination with tannins. Yellow from buckthorn (probably Rhamnus saxatilis) and red from cochineal (probably Dactylopius coccus) were found mixed with synthetic dyes in green and dark red embroidery threads, respectively. Early synthetic dyes were identified in all the other colours. These include Rhodamine B (C.I. 45170), Orange II (C.I. 15510), Orange IV (C.I. 13080), Metanil Yellow (C.I. 13065), Chrysoidine R (C.I. 11320), Methyl Violet (C.I. 42535), Malachite Green (C.I. 42000), Fuchsin (C.I. 42510), Auramine O (C.I. 41000) and Methyl Blue (C.I. 42780). As the date of the first synthesis of these dyes is known, the production date of the garments was refined, suggesting that these were likely to be produced towards the end of the 1880s/beginning of the 1890s. The continuous use of historical local sources of natural dyes, alongside new synthetic dyes, is of particular interest, adding rightful nuances to the development of textile-making practices in this region. Full article

The industrial and artisanal textile industries necessitate the adoption of sustainable dyeing practices. Although the natural dye derived from Dactylopius coccus presents a viable option, its traditional application requires metallic mordants that pose environmental and health risks. This study investigates the utilization of atmospheric-pressure plasma jet (APPJ) technology for dyeing wool with Dactylopius coccus dye, with the objective of optimizing the process and minimizing its environmental impact. The APPJ technique was employed for wool dyed with Dactylopius coccus dye, and the textile properties, medullation, and colorimetry were evaluated using an optical fiber diameter analyzer (OFDA) and a spectrometer with an integrating sphere. The results demonstrated that the APPJ enhanced the color intensity and uniformity, facilitating improved dye penetration into the fibers. Plasma treatment darkened the fiber, generated reddish and yellowish tones, and increased the color saturation and intensity. The wool samples treated with plasma exhibited an increase in DMF and SF but a decrease in IC and greater size variability. The APPJ reduces total medullation in wool dyed with cochineal dye. In conclusion, the APPJ was demonstrated to be a promising method for dyeing wool with Dactylopius coccus dye, offering an effective and sustainable alternative to traditional methods, with enhanced color vibrancy and uniformity and reduced resource utilization. Full article

Carminic acid is a natural pigment typically found in several insect taxa, including specific insects such as “grana cochinilla fina” in Mexico (Dactylopius coccus Costa). Commercially, it is also referred to as carmine, which is a more concentrated solution presenting as at least 50% carminic acid. To date, this dye has been used in the pharmaceutical, food and cosmetic industries. Unfortunately, one of the main limitations has to do with establishing the appropriate extraction and purification protocol. Currently, there is growing interest in developing eco-friendly and efficient pigment extraction processes for various applications. In this study, we compare the ultrasound- and microwave-assisted extraction versus with a conventional method to obtain carminic acid from cochineal. To do this, we considered three factors that influence the extraction process as independent variables: solvent volume, temperature and irradiation time. The optimization was carried out using the response surface methodology, employing a three-factor and three-level Box–Behnken experimental design. Carminic acid contents were quantified by UV–Vis spectroscopy, and extracts were evaluated by infrared spectroscopy to verify the integrity of the carminic acid molecule. The yield obtained by ultrasound-assisted extraction was 49.2 ± 3.25, with an efficiency of 31.3 mg/min, while microwave-assisted extraction showed a yield of 40.89 ± 2.96, with an efficiency of 27.3 mg/min. Both methods exceeded the extract yield (31.9 ± 3.4%) and efficiency (10.6 mg/min) obtained with the conventional method, demostrating that ultrasound- and microwave-assisted extraction are viable alternatives for obtaining carminic acid, with the potential to be scaled up to an industrial level. Full article

In this compilation, the focus is on the Cochineal insect (Dactylopius coccus Costa, 1835 (Hemiptera: Dactylopiidae)), a creature native to South America that produces a potent natural red pigment known as “carmine”. This pigment, utilized for obtaining the color red, has been an integral part of the art world for thousands of years. Indigenous cultures, in particular, have employed the dye extracted from this insect in the creation of textile dyes and paintings. Moreover, the Cochineal insect and its unique pigments have not only supported artistic expression but also captivated and inspired artists. During the Renaissance period, artists preferred the carmine pigment produced by the females of the Cochineal insect for obtaining bright and vivid red tones. This study delves into the history of the Cochineal insect, its role in art, and its perception in the modern world. Famous paintings created with dyes obtained from the Cochineal insect are discussed, exploring how pigments have found a place in the art world and how artists have utilized this extraordinary source to create distinctive works. Full article

The extensive utilization of dyes across diverse industries has resulted in environmental pollution, leading to the degradation of water bodies. To prevent environmental contamination, the use of eco-friendly dyes and innovative processes for dye degradation is crucial. This study aimed to investigate the color removal process of cochineal dye (Dactylopius coccus Costa) using the atmospheric pressure plasma jet (APPJ: Atmospheric Pressure Plasma Jet) technique. The dye extracted from the cochineal insect was treated with APPJ and the resulting color removal process was analyzed. Optical emission spectroscopy (OES) was used to investigate the plasma emission lines, and UV-Vis spectroscopy was used to monitor the color removal process. The results revealed that the decolorization of cochineal dye was a result of an oxidative degradation process caused by the interaction of the reactive species (NO₃⁻ and NO₂⁻) generated by the APPJ plasma discharge with the dye molecules. This color removal process occurs in an acidic medium, leading to a pH change from 5.4 to 2.7. These pH changes can be attributed to fluctuations in the concentrations of reactive species such as nitrates and nitrites in the liquid phase. UV-Vis spectroscopy measurements showed that 90% of the cochineal color was removed within the first 10 min of treatment. This study enhances our understanding of natural color removal and provides insights into its mechanism, opening up possibilities for controlled modification and applications in various fields. Full article

In the present work, a method is proposed that combines spectrofluorimetry with multivariate analysis (cluster and principal components) to non-invasively investigate natural dyes used, mainly in the form of lakes, in illuminations. First, a consistent number of mock-up samples of red and purple lakes (from brazilwood, madder, kermes, cochineal, lac dye, folium and orcein) were prepared following the recipes reported in ancient treatises, then the experimental conditions for their non-invasive investigation were optimized by benchtop instrumentation and transferred to a portable microprobe suitable for in situ analyses. For all the coloring materials examined, it was thus possible to obtain a satisfactory grouping of samples containing the same dye. The analytical protocol was finally extended to the characterization of dyes in the Crescenzago choir books, illuminated manuscripts dating back to the end of the 15th century. Full article

The traditional shirt (“ie”) is the most well-known element of Romanian anonymous textile art. Apart from aesthetic and utilitarian roles, it has strong symbolic significance, mainly through the colours used for decoration. Very recently, the traditional shirt with decoration over the shoulder (“ia cu altiță”) was introduced as a Romanian identity element as part of UNESCO heritage. Depending on the ethnographic area, the traditional shirt with decoration over the shoulder has acquired special expressive particularities over time. Particularly relevant is that from Valea Hârtibaciului, an area of Transylvania in the very centre of Romania. Although sober in appearance with large fields of white plain weave, it is discreetly decorated with elaborated embroidery on the sleeve bracelets, over the shoulders and neck. Even the colour range and decoration motifs remain unchanged in time, evolution in the materials used and a subtle transition from natural hues to more strident alternatives were observed in the late 19th and early 20th centuries. For the present study, samples were taken from representative objects in the collections of the ASTRA Museum, Sibiu and Ethnographical Museum, Brasov, documented as belonging to the area of Valea Hârtibaciului and dated in the museum archives as from the late 19th and early 20th century. The textile materials and the dyes used in the shirts’ embroidery were monitored. Fibre identification was made by optical microscopy and infrared spectroscopy (FTIR-ATR). Dye analysis was performed by liquid chromatography coupled with UV-Vis (diode array) detection, while some of the samples were also analysed by liquid chromatography coupled with mass spectrometric detection (LC-DAD-MS). Dyes were extracted from the fibres by acid hydrolysis. Identification was based on data collected on standards, dyes and dyed fibres. For the early synthetic dyes, a dedicated library of references was built, which includes information relative to the most relevant representatives used between 1850 and 1900, the ‘Helmut Schweppe list’. According to the study, in the last decades of the 19th century, natural dye sources such as dyer’s broom, madder, Mexican cochineal and indigoid dyes were gradually replaced by early synthetic dyes: fuchsine (1856), methyl violet (1861), synthetic alizarin (1871), brilliant green (1879), azo flavine 3R (1880), rhodamine B (1887) and others. Full article

Natural dyes are not harmful to the environment owing to their biodegradability. For dye application to textiles, salts are necessary as mordant or electrolytes and make an environmental impact. In this paper, the influence of cationization during mercerization to the dyeing of cotton fabric with natural dye from Dactylopius coccus was researched. For this purpose, bleached cotton fabric as well as fabric cationized with Rewin OS was pre-mordanted using iron(II) sulfate heptahydrate (FeSO₄·7H₂O) and dyed with natural cochineal dye with and without electrolyte addition. For the characterization of surface changes after cationization, an electrokinetic analysis on SurPASS was performed and compared to pre-mordanting. For determination of dye exhaustion, the analysis of dye solution was performed on a UV/VIS spectrophotometer Cary 50 Solascreen. Spectrophotometric analysis was performed using a Datacolor 850 spectrophotometer, measuring remission ”until tolerance” and the whiteness degree, color parameters, color depth (K/S), and colorfastness of dyed fabric were calculated. Levelness was determined by visual assessment. Cationized cotton fabrics showed better absorption and colorfastness. Pre-mordanting and cationization showed synergism. The electrolytes improved the process of dye absorption. However, when natural dyeing was performed on cotton fabric cationized during mercerization, similar chromacity, uniform color, and colorfastness were achieved with and without electrolyte, resulting in pure purple hue of cochineal. For achieving a violet hue, pre-mordanting with Fe-salt was needed. Therefore, salt can be reduced or even unnecessary, which makes this process of natural dyeing more environmentally friendly. Full article

Effective analytical approaches for the identification of natural dyes in historical textiles are mainly based on high-performance liquid chromatography coupled with spectrophotometric detection and tandem mass spectrometric detection with electrospray ionization (HPLC-UV-Vis-ESI MS/MS). Due to the wide variety of dyes, the developed method should include an adequate number of reference color compounds, but not all of them are commercially available. Thus, the present study was focused on extending of the universal analytical HPLC-UV-Vis-ESI MS/MS approach to commercially unavailable markers of red, purple, and blue dyes. In the present study, HPLC-UV-Vis-ESI MS/MS was used to characterize the colorants in ten natural dyes (American cochineal, brazilwood, indigo, kermes, lac dye, logwood, madder, orchil, Polish cochineal, and sandalwood) and, hence, to extend the analytical method for the identification of natural dyes used in historical objects to new compounds. Dye markers were identified mostly on the basis of triple quadrupole MS/MS spectra. In consequence, the HPLC-UV-Vis-ESI MS/MS method with dynamic multiple reaction monitoring (dMRM) was extended to the next 49 commercially unavailable colorants (anthraquinones and flavonoids) in negative ion mode and to 11 (indigoids and orceins) in positive ion mode. These include protosappanin B, protosappanin E, erythrolaccin, deoxyerythrolaccin, nordamnacanthal, lucidin, santalin A, santalin B, santarubin A, and many others. Moreover, high-resolution QToF MS data led to the establishment of the complex fragmentation pathways of α-, β-, and γ- aminoorceins, hydroxyorceins, and aminoorceinimines extracted from wool dyed with Roccella tinctoria DC. The developed approach has been tested in the identification of natural dyes used in 223 red, purple, and blue fibers from 15th- to 17th-century silk textiles. These European and Near Eastern textiles have been used in vestments from the collections of twenty Krakow churches. Full article

In the present study, four natural textiles (cotton, linen, wool, and silk) were dyed with 14 naturally extracted dyes, and pancreatin enzyme was used in the dyeing process. The effects of pancreatin enzyme and its buffer on naturally dyed textile samples were evaluated. Two concentrations of pancreatin enzyme and buffer were used as pretreatments for dyed textiles. Proteinic fabrics showed the highest relative color strength (RCS) values of 137.23% and 132.2% when the pancreatin enzyme was applied on wool and silk dyed with pomegranate skin and bloodroot at concentrations A and B, respectively. Linen fiber dyed with catechu tree showed the highest total color difference (TCD) values with buffer (6.83) and pancreatin enzyme A (5.7) and B (6.3). This shows that there were no side effects of the pancreatin enzyme on the studied dyed textiles. By high-performance liquid chromatography (HPLC) analysis, the root extract from madder showed the presence of salicylic acid (1758.91 mg/kg extract), quercetin (844.23 mg/kg extract), ellagic acid (784.86 mg/kg extract) and benzoic acid (582.68 mg/kg extract) as main compounds. In cochineal extract the main compounds were rutin (37.732 mg/kg extract), kampherol (1915.98 mg/kg extract), myricetin (809.97 mg/kg extract), quercetin (496.76 mg/kg extract) and salicylic acid (193.87 mg/kg extract). Full article

C.I. Natural Red 4 dye, also known as carmine or cochineal, was adsorbed onto the surface of spongin-based fibrous skeleton of Hippospongia communis marine demosponge for the first time. The influence of the initial concentration of dye, the contact time, and the pH of the solution on the adsorption process was investigated. The results presented here confirm the effectiveness of the proposed method for developing a novel dye/biopolymer hybrid material. The kinetics of the adsorption of carmine onto a marine sponge were also determined. The experimental data correspond directly to a pseudo-second-order model for adsorption kinetics (r² = 0.979–0.999). The hybrid product was subjected to various types of analysis (FT-IR, Raman, ¹³C CP/MAS NMR, XPS) to investigate the nature of the interactions between the spongin (adsorbent) and the dye (the adsorbate). The dominant interactions between the dye and spongin were found to be hydrogen bonds and electrostatic effects. Combining the dye with a spongin support resulted with a novel hybrid material that is potentially attractive for bioactive applications and drug delivery systems. Full article