Softwood Research Articles

A deep eutectic solvent with a lignin stabilization and functionalization for lignocellulosic biomass pretreatment

This study synthesized a functional deep eutectic solvent (DES) using betaine and glyoxylic acid (GA) for lignocellulosic biomass pretreatment. The Betaine/GA DES pretreatment resulted a high delignification efficiency of 81.89% and xylan removal of 83.25% while preserving most of cellulose. During pretreatment, lignin was stabilized by GA, preventing its condensation and introducing carboxyl groups onto its molecular backbone. The GA stabilized lignin (GASL), with a high β-O-4 linkage content of 62.92%, was depolymerized for phenolic monomer production with a bio-oil yield of 55.40%. Additionally, the functional lignin was used as a surfactant for GASL-based O/W emulsion (GA-O/W emulsion) preparation. With 0.5% of lignin addition and an optimal O/W ratio of 6:4, the resulting GA-O/W emulsion exhibited a high cream index value of 100% and excellent storage stability without any phase transition or emulsion aggregation. When using the lignin to prepare curcumin-encapsulated microcapsules, a cumulative curcumin remaining of 74.19% under UV radiation and an extraordinary encapsulation efficiency of 62.86% were achieved. Furthermore, this DES pretreatment promoted enzymatic saccharification of the pretreated cellulose substrate, resulting in a glucose yield of 91.49%. After adding 15 wt% of the fibers in soft wood pulp for papermaking, the tear index, ring crush strength index, and tensile index of the produced paper-sheets reached 112.04%, 98.58%, and 83.55% of those of the pure softwood pulp papers, respectively.

A Review of Cradle-to-Gate Greenhouse Gas Emission Factors for Canada’s Harvested Wood Products

Abstract With the previous decade’s (2010 through 2019) greenhouse gas emissions remaining the highest on record, focus on emissions mitigation efforts is paramount. Harvested wood products (HWPs) can store carbon for various timespans depending on the product and its end uses. Life cycle inventories (LCIs) are the base for life cycle analyses (LCAs), as they represent a comprehensive catalogue of the raw data essential to complete an LCA. However, most LCI documentation is in the form of case studies of different types of HWPs, with varying LCI results that reflect varied system boundaries, case-specific conditions, and assumptions. Our goal was to conduct a systematic literature review to evaluate, analyze, and synthesize previously reported Canadian HWP data and to initiate a Canadian database based on reported cradle-to-gate HWP emission factors. HWPs were categorized as lumber, traditional structural panels, mass timber, nonstructural panels, and wood pellets. Based on our analysis, we found that softwood lumber produced the lowest cradle-to-gate emission factor (61.99 kg of CO2 equivalent [CO2eq] per m3 HWP) while I-joists produced the highest (218.55 kg of CO2eq per m3 HWP). Resource extraction emissions accounted for most of the overall emissions for softwood lumber, oriented strand board, cross-laminated timber, and glue-laminated timber. Meanwhile, manufacturing accounted for most of the emissions for plywood, I-joists, cellulosic fiberboard, particleboard, and wood pellets. Substantial gaps exist in published LCI data and, when possible, publishing detailed LCI data is encouraged to support additional HWP life cycle analyses.

Influence of TEMPO on preparation of softwood nanofibrils and their hydrogel network properties

From an economic and environmental perspective, the use of less chemicals in the production of cellulose nanofibrils (CNFs) is advantageous. In this study, we investigated the oxidation (TEMPO/NaClO2/NaClO, pH 6.8) of softwood (SW) particles with varying amounts of TEMPO (16, 8 or 0 mg g−1 of wood). Following, TEMPO-oxidized SW nanofibrils (TO-SWNFs) were obtained by nanofibrillation and their size, morphology, and crystallite size were assessed. Hydrogel networks of TO-SWNFs were prepared and mechanical properties were measured in dH2O and phosphate buffered saline (PBS) to compare their performance for possible biomedical applications such as wound dressings. The results reveal that the presence of TEMPO is of importance for TO-SWNF network properties, presenting higher eq. H2O absorption (≈2500 %) and elongation at break (≈10 %) with good wet strength (≈180 kPa). In addition, a decrease in use of TEMPO catalyst from 16 to 8 mg g−1 of wood is possible, without detrimental effects on hydrogel network properties (dH2O absorption ≈ 2000 %, elongation at break ≈ 13 %, wet strength ≈ 190 kPa) related to applications as wound dressings.

Evaluation of bending and shear properties of mixed softwood & hardwood cross-laminated timbers

The current version of PRG-320 Standard for Performance-Rated Cross-Laminated Timber (CLT) that governs CLT manufacturing and design, limits production to softwood species. As a result, the growing demand for CLT production could strain the supply of softwood lumber in the US within the next decade. The inclusion of hardwood in CLT production alongside softwood could be a potential solution to this problem. This paper investigates the bending and shear test results of three- and five-layer mixed species CLT beams manufactured using various combinations of yellow-poplar and southern pine. The beams were evaluated for bending strength, bending stiffness, shear strength, and shear stiffness, as well as quality control testing of moisture content, specific gravity, resistance to shear by compression loading and resistance to delamination. The experimental values for all CLT groups, adjusted according to the Allowable Stress Design (ASD) to ensure stress limits are not exceeded, were greater than those calculated using the shear analogy method. The only exceptions were bending stiffness values for the groups with all layers of southern pine and those with outer layers of southern pine and inner layers of yellow-poplar (see Table 1 for layups codes), where the differences remained within a minor range of 4 %. Although, wood failure percentages in resistance to shear by compression loading fell below the maximum value of 80 %, and face delamination percentages in resistance to delamination were above the minimum value of 5 % according to the corresponding standards. The mechanical properties of all CLT beams met or exceeded shear analogy values. The test results indicated that yellow-poplar could be a viable alternative to southern pine in the production of CLT due to its similar specific gravity. This suggests that mixed-species CLT can maintain or enhance structural performance while addressing material shortages. Furthermore, the use of yellow-poplar in CLT production promotes sustainable forestry practices, supports resource diversification, and encourages innovation in construction methods. These findings have significant practical implications for the timber and construction industries, contributing to cost efficiency and environmental sustainability.

Working at home. Reconstructing activities within the LBK household through the systemic use-wear analysis of flint industries, bone and antler tools and ground stone implements

The systematic analysis of use-wear traces on flint, ground stone and bone tools, has rarely been carried out at Early Neolithic sites in continental Europe. Hence, it is a powerful means of identifying possible economic differences. As part of the ongoing HOMES project, we are investigating the importance and nature of acquisition strategies (hunting, harvesting), food preparation techniques (butchery, grain milling) and the processing of other resources (plant fibres) in a large set of LBK households in the Aisne Valley (France). After re-examining and integrating new results on the flint industry (366 tools), bone and antler tools (414 tools) and ground stone tools (114 tools), the aim here is to examine whether the processing of soft flint plants, hides and wood remains the dominant activity and how it coexists with more marginal activities such as the processing of soft minerals and textile fibres. The absence of certain activities is scrutinised in relation to their location within and outside the domestic and village space. Discrete functional characteristics are tracked to improve our understanding of the observed differences between the domestic units: segmentation of production processes, differences in the use of each type of raw material, intensity of use. In this way, we can test the hypothesis of autonomous or interdependent households in terms of production and consumption and investigate the economic structure of LBK villagers.

Advances in Blueberry (Vaccinium spp.) In Vitro Culture: A Review

The demand for Vaccinium fruits has skyrocketed due to their nutritional and medicinal properties, notably their high content of phenolic compounds and excellent sensory evaluation. The use of Vaccinium plants and its components as dietary supplements and health ingredients has been on the rise across the world. The attractive fruits contain a high content of anthocyanins and antioxidant compounds. In some popular and valuable cultivars, the conventional propagation methods, exploiting hard or soft wood cuttings, are inefficient. The demand for nursery plants can be fulfilled by micropropagation. This review aims to explore advances in the in vitro culture of Vaccinium plants, focusing on effective disinfection, optimized culture media, and the role of growth regulators in plant development and multiplication. By providing a controlled environment, micropropagation allows the large-scale production of these plants in a short time, ensuring availability throughout the year. Additionally, this technique offers the advantage of studying the effects of abiotic stresses on plants, as well as facilitating research on the production of relevant metabolites. This review seeks to provide an updated overview of the most promising methods and techniques for micropropagation of Vaccinium, thereby contributing to the ongoing development of the blueberry production industry and derivative products.

Experimental and numerical studies on influences of wedge reinforcement on seismic performance of loose penetrated mortise-tenon joints

Wooden wedges significantly affect the rotational stiffness and load-bearing capacity of penetrated mortise-tenon joints (PMTJ). To clarify the role of wedges on the seismic performance of loose penetrated mortise-tenon joints, three types of full-scale PMTJs, including reference, loose, and wedge-reinforced joints, were tested under quasi-static loading. The deformation characteristics, hysteresis curves, rotational stiffness degradation behavior, and energy dissipation of PMTJs with wedge were analyzed. Three-dimensional nonlinear finite element models were established to simulate the wedge effects, and the stress states of joint were analyzed. The results indicated that the ultimate bending moment capacity of reference and loose joints was reached when the splitting failure of tenon occurred, while the wedge-reinforced joint reached such capacity when the transverse compression failure occurred at the wedges. The maximum bending moment of PMTJ with a 10 mm gap and a 25 mm gap were 18.3 % and 55.3 % lower than that of reference joint, while maximum bending moments of wedge-reinforced joint with a 10 mm gap and a 25 mm gap were 12.6 % and 17.03 % larger than that of reference joint, respectively. Numerical simulation showed that wooden wedge reduced stress concentration in the tenon and alleviated compression damage of the tenon. Higher load-bearing capacity and rotational stiffness were observed in joints when hardwood wedges were used, compared with that of soft wood. Wedge reinforcement could effectively improve the load-bearing capacity of loose PMTJ. These results yielded valuable data for the performance evaluation and retrofitting of penetrated mortise-tenon joints with wedges in traditional timber structures.

Redox-mediated changes in the release dynamics of lead (Pb) and bacterial community composition in a biochar amended soil contaminated with metal halide perovskite solar panel waste

This study explored the redox-mediated changes in a lead (Pb) contaminated soil (900 mg/kg) due to the addition of solar cell powder (SC) and investigated the impact of biochar derived from soft wood pellet (SWP) and oil seed rape straw (OSR) (5% w/w) on Pb immobilization using an automated biogeochemical microcosm system. The redox potential (Eh) of the untreated (control; SC) and biochar treated soils (SC + SWP and SC + OSR) ranged from −151 mV to +493 mV. In SC, the dissolved Pb concentrations were higher under oxic (up to 2.29 mg L−1) conditions than reducing (0.13 mg L−1) conditions. The addition of SWP and OSR to soil immobilized Pb, decreased dissolved concentration, which could be possibly due to the increase of pH, co-precipitation of Pb with FeMn (hydro)oxides and pyromorphite, and complexation with biochar surface functional groups. The ability and efficiency of OSR for Pb immobilization were higher than SWP, owing to the higher pH and density of surface functional groups of OSR than SWP. Biochar enhanced the relative abundance of Proteobacteria irrespective of Eh changes, while the relative abundance of Bacteroidota increased under oxidizing conditions. Overall, we found that both OSR and SWP immobilized Pb in solar panel waste contaminated soil under both oxidizing and reducing redox conditions which may mitigate the potential risk of Pb contamination.

Direct synthesis of a lithium carboxymethyl cellulose binder using wood dissolving pulp for high-performance LiFePO4 cathodes in lithium-ion batteries

Lithium carboxymethyl cellulose (CMC-Li) is a promising novel water-based binder for lithium-ion batteries. The direct synthesis of CMC-Li was innovatively developed using abundant wood dissolving pulp materials from hardwood (HW) and softwood (SW). The resulting CMC-Li-HW and CMC-Li-SW binders possessed a suitable degree of substitutions and excellent molecular weight distributions with an appropriate quantity of long- and short-chain celluloses, which facilitated the construction of a reinforced concrete-like bonding system. When used as cathode binders in LiFePO4 batteries, they uniformly coated and dispersed the electrode materials, formed a compact and stable conductive network with high mechanical strength and showed sufficient lithium replenishment. The prepared LiFePO4 batteries exhibited good mechanical stability, low charge transfer impedance, high initial discharge capacity (∼180 mAh/g), high initial Coulombic efficiency (99 %), excellent cycling performance (<3% loss over 200 cycles) and good rate capability, thereby outperforming CMC-Na and the widely used cathode binder polyvinylidene fluoride.

Effect of Sugarcane Bagasse, Softwood, and Cellulose on the Mechanical, Thermal, and Morphological Properties of PP/PE Blend

The usage of cellulosic fibers as fillers for thermoplastics has generated great interest due to their numerous advantages and benefits compared to conventional fibers. This article examines a comparative study on the mechanical, thermal, and morphological properties of polypropylene/polyethylene (PP/PE)/cellulose (sugarcane bagasse (SCB) and softwood (SW)) blend composites prepared through melt compounding. The morphology of the obtained PP/PE/SCB and PP/PE/SW blend composites was investigated using scanning electron microscopy (SEM). The X-ray diffraction (XRD) analysis showed reduced crystallinity of the PP/PE blend after fiber interaction. Thermal results showed that the PP/PE/SW blend was more thermally stable compared to the PP/PE/SCB blend. Additionally, the onset temperature of main degradation decreased with th e incorporation of extracted celluloses. Differential scanning calorimetry (DSC) analysis revealed that the introduction of SCB or SW raw fiber and extracted celluloses did not significantly change the melting and crystallization behavior of the PP/PE blend. Dynamic mechanical analysis (DMA) revealed that the storage modulus of the PP/PE/SCB raw and PP/PE/SW raw materials were lower than their corresponding cellulose blend composites across the temperature range studied.

Analysis of location, feedstock availability, and economic impacts of potential mass timber processing facilities in Michigan

Mass timber, an engineered wood product, offers exceptional strength and versatility as a building material, is lightweight, which makes it easy to transport and assemble, is aesthetically appealing, and offers the potential to reduce GHG emissions. This study attempts to identify the potential locations for mass timber production in Michigan, estimate the available feedstock, and evaluate the economic impacts of mass timber production on the state's economy. Procurement zones for all softwood lumber producers in Michigan were identified and overlaid to create competition hotspots for the softwood sawtimber industry. Two potential locations were identified for mass timber production within the state. Forest Inventory and Analysis (FIA) data was used to estimate the annual sustainable availability of softwood (ASAW) for mass timber production. Finally, IMPLAN was used to assess the economic impacts associated with mass timber production in Michigan. We identified two sawmills for mass timber production and concluded that there is sufficient ASAW for mass timber production in these facilities. Producing 12,429 m3 of mass timber supports at least 93 total jobs (35 direct, 29 indirect, and 29 induced) with a total output of $12.52 million in Michigan's economy. Similarly, upgrading the capacity of existing sawmills to supply lumber for mass timber production will result in 34 additional jobs with a total output of $5.63 million.

Tree marking guidelines for northern hardwoods: a review of criteria for assessing vigour and quality

Recent studies have highlighted the need to update hardwood tree marking guides by changing the criteria used to assess vigour and quality, and thus the priority for deciding which trees to remove and retain during selection harvests. However, these studies have recommended different criteria, so it remains uncertain which should be included in the classification systems used to assess vigour and quality. We review these studies with the aim of reducing this uncertainty and identifying potential improvements to the provincial tree marking guides for northern hardwood forests in Canada, particularly the Ontario Tree Marking Guide. We review the differences in methodologies and summarize which defects have been shown to affect vigour and/or quality. The defects that should be used to assess vigour are canopy dieback, cankers, and fungi. Decaying wounds, wounds without decay, canopy density, and bark condition could also be used as secondary criteria for borderline cases in which the primary criteria are not decisive. The defects that should be used to assess quality are cankers, fungi, cracks, cavities, and decay (including black bark and wounds with moisture or soft wood). We present a new classification system based on these results and identify potential challenges to its implementation.

Thermal Decomposition and Kinetic Parameters of Three Biomass Feedstocks for the Performance of the Gasification Process Using a Thermogravimetric Analyzer

Thermogravimetric analysis (TGA) is a powerful technique and useful method for characterizing biomass as a non-conventional fuel. A TGA apparatus has been utilized to experimentally investigate the impact of biomass feedstock diversity on the performance of the gasification of hardwood (HW), softwood (SW) pellets, and refuse-derived fuel (RDF) materials. The solid conversion rate and the volatile species formation rate have been estimated to quantify the rates of devolatilization for each material. In addition, the combustion kinetic characteristics of the three biomass feedstocks were investigated using TGA at different heating rates, and a thermal kinetic analysis was conducted to describe the gasification process. Therefore, the kinetic parameters have been evaluated for different thermal reactions and non-isothermal kinetic models that depend on the relationships between heating rates and temperature profiles. The results show that the amount of tar content from the RDF was higher than that of pure hardwood and softwood feedstocks. Hence, tar removal must be part of any process using syngas produced from RDF feedstocks in a gas engine to produce electricity.

Lesser Woodcreepers excavate nest cavities in trees

Abstract To understand the evolution, life-history tradeoffs, and population ecology of cavity nesters, it is critical to identify the avian lineages and circumstances in which birds excavate tree cavities. Woodcreepers (Furnariidae: Dendrocolaptinae; 56 species) are considered non-excavators dependent on existing cavities. We overturn this assumption by providing definitive evidence that the Lesser Woodcreeper (Xiphorhynchus fuscus, 23 g) is a facultative tree-cavity excavator. From 2007 to 2022 in the Atlantic forest of Misiones, Argentina, Lesser Woodcreepers nested in preexisting tree crevices (4 nests), or excavated cavities in trunks of large-diameter trees in advanced stages of decay (mean diameter: 58 cm, range: 22–121 cm, 22 nests). Nest entrances were vertically elongated and chambers were usually pocket like, excavated in the exterior of the trees (sapwood), with floors that curved along the trees’ circumference. Excavating woodcreepers pulled out elongated pieces of spongy, fibrous decayed wood, tapping only when inside cavities. Published and online photographs of nests of Xiphorhynchus species suggest that excavation may be widespread in the genus. Our observations that woodcreepers tore out elongated pieces of spongy wood (rather than hammering) are consistent with the idea that their long, thin bills are more resistant to torsion and less resistant to impact compared to the stouter bills of other excavators in Passeriformes and Piciformes. Research has tended to focus on birds with chisel-shaped bills, perforating harder sapwood to create nesting chambers in the center of heartrot-infected trees (resulting in typical woodpecker cavities, with circular floors). We hypothesize that Lesser Woodcreepers have adopted an alternative strategy, selecting large trunks with soft outer wood (sapwood), stopping their excavation radially if they reach harder wood, and then expanding the nest chamber laterally. Furnariidae may offer a useful model family for understanding ecological and evolutionary factors that influence cavity excavation. We provide a Spanish translation in Supplementary Material.

Adsorption mechanisms and optimal production of magnetic biochar composites from red mud and soft wood biomass

We investigated the adsorption capacity of four composites generated by co-pyrolyzing red mud, an iron rich waste product from the production of alumina, together with Canadian soft wood biomasses, including Douglas fir, pine wood, red cedar and hemlock. Pyrolysis conditions included manually mixing of both biomass and red mud together before pyrolyzing at 800 °C for 3 h, with a ramp rate of 10 °C/min and a flow rate of 2 mL/min of CO2. Differences in the surface functional groups and aromaticity were observed in the biochars produced from these biomasses. It was found that oxygen containing functional groups had a greater impact on π-π electron-donor acceptor interactions, whereas greater amounts of carbonyl groups increased the adsorption of compounds with electron donating groups over compounds with electron withdrawing groups. Furthermore, optimal ratios of biomass to red mud were investigated for co-pyrolysis to achieve both strong adsorptive and magnetic properties. A greater biomass content during co-pyrolysis showed greater adsorptive properties, while only a small amount of red mud, as low as 10 wt%, was sufficient to provide the desired magnetic properties. This work was able to successfully produce an adsorbent capable of adsorbing up to 32.8 mg/g of acetaminophen by co-pyrolyzing red mud and pine wood biomass at a 9:1 ratio. The resulting composite also maintained magnetic properties, allowing the adsorbent to be easily removed from water after adsorption.

Optimization of durable superhydrophobic wood with superstrong ultraviolet resistance and chemical stability

The less UV durability and weak chemical stability of superhydrophobic wood limited its wide application. Cu2(OH)3Cl nano particles, epoxy (EP), vinyltriethoxysilane (VTES), and room temperature vulcanized silicone rubber (RTV) were combined together to modify both soft and hard wood with function of superhydrophobic at once successfully. The modified wood was endowed not only superhydrophobicity as expected, such as CA more than 150°, along with anti-fouling and self-cleaning properties, but also excellent durability, including well chemical, sandpaper abrasion, water impact and tape peeling stability. Most prominently, there was almost no color changing being observed on the modified samples. Furthermore, the best UV resistance, 3168 h consistently against UV irradiation, was achieved in the field of wood superhydrophobic modification. The proposed synergistic protective mechanism by synthesizing silicon dioxide and siloxane has potential to extend the service life and improve the high value utilization of wood product.

Sustainable, efficient, and synergistic photocatalytic degradation toward organic dyes and formaldehyde gas via Cu2O NPs@wood

Cuprous oxide (Cu2O) nanoparticles (NPs) was anchored on wood by simple spraying method, then both soft and hard wood has been endowed efficient function photocatalytic degradation toward organic dyes and formaldehyde gas synergistically. The best recycle ability of wood based photocatalyst toward organic pollutants was achieved, which was characterized by photocatalytic degradation efficiency of methylene blue (MB) more than 95% after 100 cycles, and formaldehyde gas over 85% after 60 cycles. Cu2O NPs@wood performed much lower forbidden bandwidth (Eg), which accelerated to generate much more radical of e− and finally promoted the capacity of photocatalytic degradation. The proposed Cu2O NPs@wood catalysts has potential to be applied both in the field of wastewater and air pollution remediation.

Design and Evaluation of a Shear Analogy Tool for Custom Cross-Laminated Timber (CLT) Panels Made from Various Wood Species

Abstract A user-friendly cross-laminated timber (CLT) design tool called SAM-CLT was developed to calculate the minimum design values for custom CLT panels. Custom panels are those made from different species not currently included in APA PRG 320 and include the use of multiple species in a panel. The tool uses the design value of hardwood and softwood lumber published in the national design specification book to design custom CLTs and the standard CLT grade lumber specification values published in PRG 320 standard. SAM-CLT was designed based on the shear analogy model and is intended to assist CLT manufacturers, construction and design companies, and researchers in designing and evaluating CLTs’ deformation when using different lumber types and thicknesses. This project included the calibration and validation of the tool, followed by examples of its use by computing the design value of the softwood, hardwood, and softwood–hardwood hybrid CLTs. The SAM-CLT tool was adjusted to match the published standard design values on PRG 320 and validated by comparing output for standard CLT layups. In the next step, SAM-CLT tool was used to calculate the minimum design value of custom CLTs made from hardwood–yellow poplar lumber and softwood–southern yellow pine lumber. Based on observed validation results of the tool and its application results to determine the design values for various CLT layups, this project concludes that SAM-CLT can be a valuable tool for designing custom CLTs, evaluating CLTs’ strength properties, and promoting heterogeneous lumber types in CLT manufacturing.

Quality control of wood treated with citric acid and sorbitol using a handheld Raman spectrometer

Wood modification using polyesterification of sorbitol and citric acid is a novel environmentally friendly strategy for wood protection improving its dimensional stability and acts against fungal deterioration. Inelastic Raman scattering is sensitive to the molecules of high polarizability and both lignocellulose and aliphatic esters formed during the treatment are polar. Therefore, in the present study, the quality control of the treatment using a handheld Raman spectrometer equipped with 830 nm laser is suggested as a rapid and reliable approach. Raman spectra from six wood modification levels (resulting in different weight percent gain, WPG) of three different wood species (Silver birch, Scots pine and Norway spruce) as well as three sample preparation strategies (intact, sanded and milled wood samples) were collected, and further analyzed using a chemometric method. Best performing models based on Powered Partial Least Squares Regression predicted the WPG level at R2 = 0.85, 0.95 and 0.98 for birch, pine and spruce, respectively. In addition, a clear separation between hard and soft wood species was also captured. Especially for softwood species, the sample preparation method affected the model accuracy, revealing the best performance in milled material. It is concluded that by using handheld Raman spectrometer it is possible to perform accurate quality control of wood modified by polyesterification of citric acid and sorbitol.

Black, Red and White: Characterization of Painting Materials on a Group of Bwa Masks from Burkina Faso

The distinctive and visually striking wooden masks associated with the Bwa culture in Burkina Faso, West Africa, are carved from a soft wood into different shapes and display various geometrical patterns and symbols according to their purpose. One of their characteristic features is the use of the colors black, red, and white, which evoke the three major rivers crossing the country: the Black, Red, and White Voltas. According to published accounts of scholars who have worked directly with the artists, the materials used to obtain these colors include reptile excrement for the white, iron-rich stones powdered and mixed with egg or plant gums for the red, and boiled Acacia seed pods for the black, as well as modern materials such as enamel paint in some cases. A group of four Bwa masks in the Arts of Africa collection of the Art Institute of Chicago was investigated using a complement of analytical techniques including Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, pyrolysis gas chromatography–mass spectrometry, and mass spectrometry-based proteomics to characterize their painting materials. The results obtained corroborate the published accounts, while also providing new insights into the nature of the coloring materials and the selection and substitution of pigments and binders. These findings highlight the complementary value of scientific research, in combination with fieldwork and artists’ accounts, to generate a fuller understanding and appreciation of this traditional artistic practice.