Black Pigment Research Articles

Carbon black dispersing agents based on fully hydrophilic poly(N‐vinylamide): Surface adsorption via selective interactions

AbstractInterface‐stabilizing polymers are frequently used in commercial applications to provide long‐lasting dispersions of colloids in liquid media. Dispersing high concentrations of pigments in aqueous solution can be particularly challenging. Here, we present a novel, fully hydrophilic dispersing agent system for carbon black (CB) pigments based on partially hydrolyzed poly(N‐vinylamides). These highly water‐soluble polymers adsorb onto CB through specific interactions between the polymer and surface‐bound moieties, rather than the hydrophobic effect. They participate in hydrogen bonding, ion–dipole interactions and can be partially positively charged to engage in ion pair formation, providing strong surface affinity. Dispersants are synthesized using free radical copolymerization of N‐vinylform‐ and ‐acetamide, acidic hydrolysis, and subsequent PEGylation. Molecular water solubility of the synthesized polymers is confirmed by using fluorescence spectroscopy. Highly concentrated CB dispersions are prepared in acidic, neutral, and basic media, which we identify to strongly affect the interactions between polymer and CB. The stability of CB dispersions is analyzed using ultracentrifugation and thermogravimetric analysis. The presented polymers are able to provide significantly more stable dispersions than a commercial reference product, showcasing the suitability of poly(N‐vinylamines) as potent CB dispersing agents.

Discovering manganese-based blacks in the grave goods of Kha and Merit (Egypt, 1450-1400 BCE): Multidisciplinary investigation on use and nature

As part of the “TT8 Project”, several research groups examined the grave goods from the Theban Tomb No. 8 of Kha and his wife Merit who lived during the second half of 18th dynasty and were discovered by the Italian Archaeological Mission led by Ernesto Schiaparelli. Thanks to the collaboration of Egyptologists, conservators, and scientists, numerous state-of-the-art, non-invasive methods were used to examine and characterize the objects found in the tomb.During this comprehensive investigation, for which a fully non-invasive approach was designed, the preliminary results for three polychrome wooden caskets showed the unexpected presence of manganese in the black areas in combination with the carbon black ink also present in the black decorations.In addition to MA-XRF analysis, which allowed for the discovery, an innovative imaging method was applied for faster discrimination of black pigments. This method is based on the optical spectral differences between manganese-based blacks and carbon black in the short-wave infrared – with a maximum difference in the range of 1400–1700 nm – and is comparable to a photograph in terms of acquisition time. By using an InGaAs camera with an interferential long-pass filter of 1400 nm, the images were acquired first on a series of mock-ups and then on the wooden caskets. Using false color imaging representation, the areas painted with manganese black showed a clear red false color, in contrast to the black false color of the areas painted with carbon black. The results are fundamental to understanding whether the use of manganese black could be more widespread than reported in the literature so far.

Genetic analysis of platelet-derived growth factor receptor-like gene (PDGFRL) polymorphism and melanin traits in Lanping black-boned sheep (Ovis aries)

Abstract. In the intricate tapestry of Yunnan Province's biodiversity, the Lanping black-boned sheep (LPBB) emerges as a captivating enigma, distinguished by its profound melanin pigmentation adorning both its skin and its internal organs. Initially cataloged in the 1950s within the confines of Lanping County, this exceptional mammalian species presents a scarcity and uniqueness that extends beyond its geographic origins. Here, we collected 100 blood samples from Lanping black-boned sheep along with 50 samples each from Lanping normal sheep (LPN) and Huize normal sheep (HZN), all sourced from Yunnan Province. Our investigation focused on the association between the platelet-derived growth factor receptor-like gene (PDGFRL) polymorphism and the distinctive melanin characteristics observed in Lanping black-boned sheep. Utilizing UV–visible spectrophotometry, we assessed the melanin indexes present, such as tyrosinase activity and true melanin in the sheep blood, and the results demonstrated a significant elevation in melanin indexes for Lanping black-boned sheep compared to the control group (P<0.05). We also identified three synonymous mutation sites within a partial 1128 bp exon fragment of the gene-encoding PDGFRL (EX2-G408A, EX5-T184C, and EX5-G222T). Notably, Lanping black-boned sheep, harboring genotypes GG, TT, and GG at these specific sites, showcased a pronounced surge in tyrosinase activity, eumelanin / total melanin ratios, and plasma colorimetric values when contrasted with the control group (P<0.05). The discernment of GG, TT, and GG as the prevailing genotypes at their respective genetic loci in Lanping black-boned sheep heralds a breakthrough in our understanding of the genetic markers associated with black pigmentation. However, all three loci are silent mutations and do not alter the phenotypic changes. Whether they affect changes in melanin content through other metabolic pathways requires further study. In conclusion, the PDGFRL gene was silenced by mutations in our study and affected blood melanin levels. However, the gene did not undergo a missense mutation that altered the phenotypic changes, and the exact channel through which the changes in melanin content were affected needs to be further verified.

Agricultural Pesticide-Induced Physiological Stresses in Freshwater Fishes of Bangladesh

In Bangladesh, most croplands are situated in floodplains, enriched by numerous rivers and extensive freshwater wetlands. These areas also support productive open-water fisheries, crucial for supplying protein, generating income, creating jobs, and boosting the GDP. However, the widespread use of pesticides in these floodplains to protect crops and enhance food production leads to significant environmental issues. Agricultural pesticide residues enter water bodies through runoff, rainwater, drainage, seepage, and spray drift, contaminating natural water bodies and exerting continuous stress on aquatic life, including fish. Previous studies have detected pesticide residues in surface waters, sediments, and fish in Bangladesh, posing a major threat to wetland ecosystems. Research on freshwater fish species in Bangladesh has highlighted toxic effects on fish gonads, such as adhesion, inter-follicular space degeneration, ovigerous lamellae degeneration, necrosis, degenerated perinucleolar oocytes, cytoplasmic retraction in ovaries, and damage to sertoli cells. Additional observed effects include irregularly shaped seminiferous tubules, breakage of seminiferous tubules, and empty lumens in testes. Pesticides also inflict harm on other internal organs of fish, with gill effects like clubbing, reduction of gill filaments, telangiectasia of gill lamellae, hemorrhage, and damage to gill rakers. Kidney and liver damage include necrosis, cellular tissue degradation, acute cellular swelling, and irregular renal corpuscles, along with autolysis, vacuolation, and fatty changes in the liver. Developing embryos and larvae of freshwater fish are particularly vulnerable to the toxic effects of agro-pesticides. Studies reveal acute toxicity during early life stages, evidenced by deformities like edema, notochord deformity, caudal fin damage, yolk sac damage, posterior region damage, tissue fragmentation, black pigmentation on the yolk, body curvature, and lordosis in larvae. Exposed embryos exhibit deformities such as dark brown yolk sacs, notochord deformities, and broken eggshells. Mortality rates of fish embryos and larvae escalate with higher pesticide concentrations in water. Haemato-biochemical parameters serve as crucial indicators of pesticide exposure in fish studies, showing alterations in blood hemoglobin, glucose, RBC, WBC counts, and various erythrocytic abnormalities like twin cells, fusion, echinocyte formation, spindle-shaped, tear-drop, and elongated cells. Nuclear abnormalities include binucleated cells, nuclear buds, nuclear bridges, karyopyknosis, and notched nuclei. Research suggests that even at low concentrations, agro-pesticides disrupt physiological functions and life history traits of fish, adversely impacting the natural productivity and biodiversity of freshwater fish in Bangladesh.

Effects of NIR-reflective pigments on waterborne polyurethane coatings and their thermal insulation performance

Waterborne coatings have garnered much attention and gradually occupied the coating market recently due to the significant advantages in volatile organic compound emissions compared with solvent-borne coatings. Waterborne polyurethane coatings are a majority portion of waterborne coatings. Unlike solvent-borne coatings, the film formation of waterborne coatings occurs in an inhomogeneous phase, which brings a challenge for pigmentation in waterborne coatings. However, the influence of pigment on film formation and the property of waterborne polyurethane coating remain unclear. In this study, the different contents of commercial black near-infrared (NIR) reflective pigments were incorporated into both commercial and synthetic waterborne polyurethane systems. The film formation process was monitored by multispeckle diffusing wave spectroscopy. The impact of the pigment content on dry films was assessed through scanning electron microscope, color and gloss measurements, dynamical thermal analyzer, and tensile testing. Furthermore, the thermal insulation performance of the waterborne polyurethane coatings was evaluated to study the function of the NIR reflective pigments. Our findings reveal that the addition of black NIR reflective pigments yields a multifaceted effect on film formation and coating morphology and improves thermal insulating property. Elevated pigment content correlated with increased crosslinking density, tensile stress, and Young's modulus.

Pigmented Rice: A Source of Health and Longevity

Rice of different varieties forms the staple food of more than half of the population in the world and is the leading cereal crop in many developing countries of the world. About half of the world population consumes rice as their major source of carbohydrate however it is also consumed as a source of protein in many countries. Rice comes in many shapes, sizes and color and thus its nutritional quality, cooking and uses vary accordingly. It is not only the white rice which contributes to these production figures, but it are available in many colors and pigments including black, purple, brown and red. The yellow, green, brown, red, purple and black colors of the rice have neutraceutical properties and hold the potential to promote health and improve metabolism. Black rice, also called "emperor's rice," has a thin layer of black bran, due to the presence of the purple/ black pigment biochemically termed as 'anthocyanin'. It is a rich source of antioxidants along with other nutrients including B vitamins (thiamine, niacin), vitamin E, magnesium, phosphorous, iron and dietary fibers. Similar to normal white rice, pigmented/ black rice is also glutinous and is relished for its nutritional significance of being low in fat, sugar and salt it is also free from gluten and cholesterol. Not only the historical evidence but modern research findings also support the claim of pigmented rice being 'super food' of twenty-first century. It has wide health benefits including lowering risk of obesity, anti-ageing, anti-cancerous, anti-diabetes and many more. Its consumption even in limited amounts acts as a savior from many serious diseases and illnesses. Due to its nutritional composition and various health benefits, it is considered as a functional food. The presence of anthocyanin, the pigment that imparts it a specific colour and holds antioxidant properties supports health and longevity. The present review reflects the nutritional profile and significant benefits of pigmented rice including its food uses so that the commodity can be popularized and utilized by the population for gaining various health benefits.

Fabrication of black wolfberry anthocyanin-based hydrogels for monitoring freshness and extending shelf-life of Dolang lamb

In this study, a black wolfberry anthocyanin-based indication label (BWIL) was developed using black wolfberry pigment (BWP) in combination with polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) (PVA:CMC = 4:3). The potential use of BWIL for monitoring the freshness of Dorang lamb was further investigated. As revealed, physical cross-linking occurred between PVA, CMC and BWP during the preparation of BWIL. The addition of BWP promoted the internal cross-linking, porosity, and thermal stability of BWIL significantly (p < 0.05). Specifically, BWIL showed a distinct color change when exposed to the refrigerated conditions of Dorang lamb. After 6 days, 12 days and 16 days of lamb refrigeration, the ΔE of BWIL was 26.3, 28.6 and 30.7, respectively, which far exceeded the human eyes' color threshold discernible (ΔE = 3.5). Besides, the ΔE of BWIL was significantly correlated with pH, fat oxidation, and TVB-N content of Dorang lamb (p < 0.05). This result indicated that BWIL could be used for identifying the freshness of lamb accurately. Importantly, the shelf-life of lamb with BWIL was extended from 6 days to 16 days, which suggests that BWIL would be an effective tool for real-time freshness monitoring and shelf-life extending of Dorang lamb.

Assessment of the Biodegradability and Compostability of Finished Leathers: Analysis Using Spectroscopy and Thermal Methods.

In this study, the biodegradation properties of leather treated with various finishing chemicals were evaluated in order to enhance the sustainability of leather processing. We applied advanced analytical techniques, including FT-IR, thermogravimetric analysis (TGA), and solid-state NMR spectroscopy. Leather samples treated with different polymers, resins, bio-based materials, and traditional finishing agents were subjected to a composting process under controlled conditions to measure their biodegradability. The findings revealed that bio-based polyurethane finishes and acrylic wax exhibited biodegradability, while traditional chemical finishes like isocyanate and nitrocellulose lacquer showed moderate biodegradation levels. The results indicated significant differences in the biodegradation rates and the impact on plant germination and growth. Some materials, such as black pigment, nitrocellulose lacquer and wax, were beneficial for plant growth, while others, such as polyurethane materials, had adverse effects. These results support the use of eco-friendly finishes to reduce the environmental footprint of leather production. Overall, this study underscores the importance of selecting sustainable finishing chemicals to promote eco-friendly leather-manufacturing practices.

Living Ink to scale up algae black pigment

Living Ink to scale up algae black pigment

Black Carbon Pigment from Coconut Shell Sawit Innovation Inkjet Printing Ink for Acrylic Polymer Styrene Textile Fabric

This research proposes an innovation in the development of inkjet printing ink that uses black carbon pigment obtained from palm coconutshells. The main objective of this study was to look at thecharacterization of textile inkjet ink from the black carbon pigments of the palm coconut shell. The black carbon pigment produced from the coconut coat has been identified as the source of the pontentionalprinting ink of the textile fabric based on the polymer of acrylic styrene. The research method involves the extraction and purification of carbon pigments from palm coconut shells, as well as the formulation of inkjetprinting. The composition of the textile inkjet used in this study is that black carbon pigments come from palm coconut shells while the adhesives used are acrylic styrene, aquadest, potassium hydroxide (KOH), poly (natrium 4- styrenesulfonat). The research included the physical characteristics of the black carbon pigments produced and the evaluation of inkjet printing textiles using pigments. Textile inkjetcharacteristics. Results of ink testing using Binocular Microscope Scanbest sample CAST1. The results of ink pigment testing on wool fabrics and image analysis testing the lowest values are found on CAST1 sample. The result of the viscosity test that the ink viskosity value CAST1 of 13.1 is close to the value of commercial ink.

Byzantine wall paintings from San Marco d’Alunzio, Sicily: non-invasive diagnostics and microanalytical investigation of pigments and plasters

A diagnostic investigation was carried out on twelfth century Byzantine wall paintings preserved in the Museum of Byzantine and Norman Culture and Figurative Arts of San Marco d’Alunzio (Messina, Italy) on the occasion of recent restoration works. First, the wall paintings were analyzed using portable X-Ray Fluorescence (p-XRF) and Fiber Optics Reflectance Spectroscopy (FORS) to obtain a non-invasive preliminary identification of the original palette. Then, five fragments were sampled for a micro-stratigraphy study using Digital Optical Microscope (DOM), Polarizing Optical Microscope (POM), and Scanning Electron Microscopy (SEM) combined with Energy Dispersive X-ray Spectrometry (EDS) to characterize the mortars and the blue and black pigments non unequivocally identified through non-invasive techniques. The palette included mainly earthen pigments like red and yellow ochres, green earth, and more valuable lapis lazuli blue applied on a bone black layer; while the analysis of mortars found on the different apses showed the same manufacturing technique and constitutive materials: lime-based binder with the addition of quartz, and rare calcareous lithic fragments as aggregate. The obtained results shed light on the pictorial technique used for the wall paintings and allowed us to compare the Sicilian pictorial cycle with the coeval Byzantine wall paintings preserved in Sardinia and Southern Italy.

Black adenoma a rare tumor of the adrenal glands: case report and systematic review

Introduction: black adrenal adenomas (ASNs) are tumors of the adrenal cortex with black or dark brown pigment. They are made of lipofuscin, it is a rare tumor and there are only case series and reports in the literature. Material and methods: a detailed systematic review was carried out following the PRISMA guide, of a total of 231 articles submitted to screening, 38 patients can be included. Results: the mean age of presentation was 46.47 years, with a predominance of females in 76.3% of the patients, with no predilection for laterality of the affected adrenal, with a mean size of 2.9cm, 89.5% were hypersecretors, the Cushing's disease occurred in 76.5% of patients, 7.9% of patients had a pheochromocytoma, and 13.2% of patients had primary hyperaldosteronism. Discussion: ASN is a rare tumor that presents clinically as a hormone-producing tumor in young women, or in other cases, in a tomography as an incidentaloma, with tomographic characteristics that suspect malignant pathology, for which surgical treatment is granted.

Observation of a Middle Spotted Woodpecker Dendrocoptes medius with aberrant, brown-coloured plumage

Abstract Birds with atypical colours in their plumage are not uncommon however, the potential causes of such aberrations have not been widely examined. Aberrant brownish-rufous phaeomelanin is one type of plumage colour that has been recorded in numerous bird species, including those which essentially contain only eumelanin (black) pigments, including several European woodpeckers. A Middle Spotted Woodpecker Dendrocoptes medius with aberrant phaeomelanised plumage observed in the Bükk Hills, Hungary, is detailed here and an evaluation of the possible nature of this form of plumage discussed.

Orion appoints Grolman as distributor of carbon black pigments in Nordic & Baltic markets

Orion appoints Grolman as distributor of carbon black pigments in Nordic & Baltic markets

Black paintings in the late Yocavil ceramics (11th–17th centuries): Applying micro X‐ray diffraction to the study of archaeological potteries in Northwest Argentina

AbstractThe black pigments used in Late Period (11th–17th centuries) painted pottery in the Yocavil Valley were characterized. Changes and continuities in the composition of this material over an extended span were evaluated. A regional sample of 47 potsherds from the Loma Rica, San José, and Santa María styles was collected, and for the first time micro wide‐angle X‐ray scattering was used in these ceramic styles. The results indicate the simultaneous presence of iron oxides (hematite) and solid solutions of manganese and iron oxides (jacobsite–magnetite). Besides, the paints were prepared by mixing the pigments with clay‐based binding materials.

Black-Pigmented Marine Pseudomonas aeruginosa Exhibiting Anti-Bacterial Activity against Multidrug-Resistant (MDR) Wound Infection Bacteria

The urgency of multidrug-resistant (MDR) bacterial infections in wounds is a significant concern due to the high prevalence of MDR in healthcare settings. Black pigmented marine bacteria, strain PS1C, were isolated from marine sediment on Awur Beach Jepara, Central Java, Indonesia, and cultured in the laboratory. The aim of this research includes molecular identification of strain PS1C, extracting black pigment from strain PS1C, isolation of MDR bacteria from wounds, and evaluating the antibacterial activity of black pigment from strain PS1C against MDR bacteria isolates of wound infections. We examined the 16S rRNA gene sequences strain PS1C to identify the species. Then, the black pigment from PS1C was extracted using methanol: acetone (7:3) solvent. Antibacterial activity was evaluated against MDR bacteria from wounds with the microdilution method. A black-pigmented bacterium was isolated and identified as Pseudomonas aeruginosa PS1C. We found that the black pigment from P. aeruginosa PS1C can be developed as an antibacterial agent against the MDR bacterial isolate of wounds with MIC and MBC values of 6.25-12.5 mg/ml and 6.25-25 mg/ml, respectively. In conclusion, the study's findings highlight the potential of the extract of black pigment from P. aeruginosa PS1C as an antibacterial agent against wound-causing MDR bacteria and reinforce previous research into P. aeruginosa can be isolated from marine sources. Additional in vivo investigations and the identification of the antibacterial activity's mode of action are required.

Seed-Coat Pigmentation Plays a Crucial Role in Partner Selection and N2 Fixation in Legume-Root-Microbe Associations in African Soils.

Legume-rhizobia symbiosis is the most important plant-microbe interaction in sustainable agriculture due to its ability to provide much needed N in cropping systems. This interaction is mediated by the mutual recognition of signaling molecules from the two partners, namely legumes and rhizobia. In legumes, these molecules are in the form of flavonoids and anthocyanins, which are responsible for the pigmentation of plant organs, such as seeds, flowers, fruits, and even leaves. Seed-coat pigmentation in legumes is a dominant factor influencing gene expression relating to N2 fixation and may be responsible for the different N2-fixing abilities observed among legume genotypes under field conditions in African soils. Common bean, cowpea, Kersting's groundnut, and Bambara groundnut landraces with black seed-coat color are reported to release higher concentrations of nod-gene-inducing flavonoids and anthocyanins compared with the Red and Cream landraces. Black seed-coat pigmentation is considered a biomarker for enhanced nodulation and N2 fixation in legumes. Cowpea, Bambara groundnut, and Kersting's bean with differing seed-coat colors are known to attract different soil rhizobia based on PCR-RFLP analysis of bacterial DNA. Even when seeds of the same legume with diverse seed-coat colors were planted together in one hole, the nodulating bradyrhizobia clustered differently in the PCR-RFLP dendrogram. Kersting's groundnut, Bambara groundnut, and cowpea with differing seed-coat colors were selectively nodulated by different bradyrhizobial species. The 16S rRNA amplicon sequencing also found significant selective influences of seed-coat pigmentation on microbial community structure in the rhizosphere of five Kersting's groundnut landraces. Seed-coat color therefore plays a dominant role in the selection of the bacterial partner in the legume-rhizobia symbiosis.

Experimental Behavior of Solar Still Using Mixed Oxides Mn-Fe/Silicone Resin Composite as Selective Solar Absorber

In this research, the optical properties of a black pigment of mixed Mn-Fe oxides synthesized by the precipitation method dispersed in silicone resin at different concentrations for use as a solar absorber in a two-slope passive solar still were evaluated. The transmittance of different thicknesses of float glass with 0.1% Fe2O3 was also studied for use as a condenser in the construction of the solar still. Regarding the pigments, the absorbance and spectral emittance were evaluated, the floated. With the above information, both the absorbent surface and the condensers were optimized to propose the best design of the solar still. The novel hybrid material used as a selective coating in the still, which corresponds to 2.3% Mn-Fe mixed oxides, exhibited a high solar absorbance of 91.82% and a relatively low infrared thermal emission of less than 57.22%, as well as good stability to the corrosive and hot environment of the solar still, in addition to great durability over time and in real operating conditions. The float glass with the highest transmittance corresponds to a thickness of 3 mm and an average transmittance of 82.57%. The built prototype was characterized by obtaining the temperature profiles of the absorber and condensers, thermal efficiency, production and water quality. The prototype has a thermal efficiency of 29.6%, requiring only energy from the sun for its operation. The water produced by this device becomes an option for human use and consumption in accordance with current official standards, allowing supply in communities that do not have access to drinking water but have access to seawater or waters with high hardness.

Biodegradable thermochromic polylactic acid (PLA) sensor

Abstract This study investigates the development of polylactic acid (PLA) by incorporating thermochromic black pigments (TCB) at varying concentrations of 0, 0.5, 1, 2 and 3 wt% through the process of melt blending. The color transition and reversion behaviors of the resulting specimens were examined at different temperatures (−10, 10, 30, 35 and 50 °C) using colorimetric analysis. Additionally, mechanical properties, thermal characteristic and thermal stability were assessed through tensile testing, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The study revealed that an increase in TCB concentrations led to a reduction in lightness (L*). Higher pigment content enhanced thermochromic properties, resulting in more pronounced color changes. The total color difference (ΔE) remained reproducible over five cycles of heating and freezing, and this reproducibility persisted after thermal aging. Tensile strength and elongation at break exhibited improvement with increasing pigment content. Glass transition temperature (Tg) and melting temperature (Tm) of the thermochromic samples showed minimal reduction compared to that of neat PLA, which is 64.2 °C. Crystallinity degree (Xc) increased slightly by 0.2–0.92 %. The thermal stability of the PLA matrix was only marginally affected by the presence of thermochromic pigments.

Near-infrared reflective Mg0.5Co0.5-xMnxAl2O4 black pigment synthesized by spray pyrolysis: Optimization of composition and calcination temperature

Co/Mn co-substituted MgAl2O4 pigments were spray pyrolysis, and their crystal structure and optical properties were characterized with changing the Co/Mn ratio and synthesis temperature. Regardless of the Co/Mn ratio, the resulting pigments showed spinel structured MgAl2O4 phase without any impurity phase. The synthesized Mg0.5Co0.5Al2O4 and Mg0.5Mn0.5Al2O4 showed a dark blue and brown color due to the visible light absorption by the 4A2(F) → 4T1(P) transition of Co2+ and the d-d transition of Mn2+, respectively. The black colored pigment was achieved by simultaneous substituting Co2+ and Mn2+ in the Mg2+ tetrahedral site in MgAl2O4. The optical band gap of the Mg0.5Co0.5-xMnxAl2O4 pigment decreased linearly from 3.08 eV (x = 0) to 2.46 eV (x = 0.4) as the Mn2+ content increased. As a result, Mg0.5Co0.1Mn0.4Al2O4 uniformly absorbed the entire visible light and had a black color (L* = 28.10, C* = 1.68). In terms of obtaining high near-infrared reflectance and good blackness, the optimal calcination temperature of Mg0.5Co0.1Mn0.4Al2O4 was determined to be 900 °C. The optimized Mg0.5Co0.1Mn0.4Al2O4 black pigment had a good LiDAR reflectance (38 % at 905 nm) and excellent chemical stability, and showed improved heat shielding performance compared to carbon black using in black vehicles.