A growing interest in the use of naturally produced pigments for textile dyeing has led to increased efforts towards the identification of such pigments that are less toxic, more sustainable, and more stable over time than currently used synthetic compounds. This work utilised various concentrations of green, red, and yellow pigments extracted with dichloromethane from the wood‐staining fungi Chlorociboria aeruginosa, Scytalidium cuboideum, and S. ganodermophthorum, respectively, for the effective dyeing of bleached cotton, spun polyamide (nylon 6.6), spun polyester (Dacron 54), spun polyacrylic, and worsted wool. All three pigments utilised in this study show significant potential for use as textile dyes. Colour changes suggested that drip application methods were superior to submersion using dichloromethane. Colour changes as compared with the untreated fabrics were most significant on polyester, which is likely due to increased levels of polymer swelling in polyester exposed to dichloromethane.

Twelve solvents were tested for their ability to extract the pigments of Chlorociboria aeruginosa and Scytalidium cuboideum, two fungi used primarily for the spalting of decorative wood. Solvents were assessed on the basis of the saturation of pigment produced, their ability to diffuse through filter paper, and whether they reacted with the extracted pigments. Solvents that performed well in extraction testing were then tested to determine whether they could also dissolve the extracted pigment once dried. Of the solvents tested, only dichloromethane was capable of quick, non‐reactive extraction with filter paper diffusion, as well as being able fully to redissolve dried pigment extracted from C. aeruginosa. The results of this study show dichloromethane to be an ideal solvent for extracting and applying fungal pigments that offers new possibilities for spalting in which fungi do not need to be grown directly on a substrate in order to produce pigmented wood.

The extracellular colorants produced by Chlorociboria aeruginosa, Scytalidium cuboideum, and Scytalidium ganodermophthorum, three commonly utilized spalting fungi, were tested against a standard woodworker’s aniline dye to determine if the fungal colorants could be utilized in an effort to find a naturally occurring replacement for the synthetic dye. Fungal colorants were delivered in two methods within a pressure treater—the first through solubilization of extracted colorants in dichloromethane, and the second via liquid culture consisting of water, malt, and the actively growing fungus. Visual external evaluation of the wood test blocks showed complete surface coloration of all wood species with all colorants, with the exception of the green colorant (xylindein) from C. aeruginosa in liquid culture, which did not produce a visible surface color change. The highest changes in external color came from noble fir, lodgepole pine, port orford cedar and sugar maple with aniline dye, cottonwood with the yellow colorant in liquid culture, lodgepole pine with the red colorant in liquid culture, red alder and Oregon maple with the green colorant in dichloromethane, and sugar maple and port orford cedar with the yellow colorant in dichloromethane. The aniline dye was superior to the fungal colorants in terms of internal coloration, although none of the tested compounds were able to completely visually color the inside of the test blocks.

The lengthy time periods required by current spalting methods prohibit the economically viable commercialization of spalted wood on a large scale. This work aimed to compare the effects of induced spalting in 16 Pacific Northwest woods using three common spalting fungi,Chlorociboria aeruginosa, Scytalidium cuboideum, andScytalidium ganodermophthorum, with the significantly less time-consuming treatment of these woods using dichloromethane-extracted green, red, and yellow pigments from the same fungi. For pigment extracts, the dosage required for a pigment to internally color various wood species to 30% internal coverage was investigated. With few exceptions, treatment with pigment extracts outperformed induced spalting in terms of percent internal color coverage. Cottonwood consistently performed best with all three pigment solutions, although chinkapin performed as well as cottonwood with the red pigment, and Port Orford cedar performed as well with the yellow pigment. While no wood species showed 30% internal color coverage with the green pigment solution, a number of additional species, including pacific silver fir, madrone, dogwood, and mountain hemlock showed internal color coverage on the order of 20–30% for red and/or yellow. Cottonwood was determined to be the best suited wood species for this type of spalting application.

Colorfastness to washing and crocking (color loss due to rubbing) are essential qualities for any dye/fabric combination that will be used for garments or upholstery. In this study, colorfastness to washing and crocking of fabrics dyed with wood-staining fungal pigments was compared to colorfastness of commercial dyes using an alternative mechanical testing method. Overall, wood-staining fungal pigments out performed commercial dyes for colorfastness to washing and wet and dry crocking. Xylindein was the most colorfast dye. Draconin red yielded inconsistent results, and the yellow pigment required a mordant to achieve any colorfastness. This study showed that the mechanical color reading method, along with statistical analysis, provided an objective, repeatable gauge of colorfastness, although visual inspection is also needed for practical purposes.

Colorfastness to light is an essential quality for textiles exposed to sunlight for a significant length of time. In this study, the colorfastness (specifically to light) of fabrics dyed with wood-staining (spalting) fungal pigments was compared to the colorfastness of commercial dyes. A short-duration immersion dying method without heat was used to minimize both water and energy usage. Both mordanted and unmordanted fabrics were tested and compared for colorfastness. Additionally, a new method of testing for colorfastness to light was developed. Results indicate that the wood-staining fungal pigments demonstrate superior colorfastness to light over commercial dyes when the employed dyeing method is used. Additionally, the colorfastness to light testing method developed using the L-2 Blue Wool Standard and QUV Accelerated Weathering Machine is a viable alternative to current standard colorfastness to light testing methods.

Twenty-one wood species native to the Pacific Northwest region of the United States, including conifers, were tested to determine if any of the commonly utilised melanin producing spalting fungi could generate sufficient spalting coverage to compete within the decorative woods market. Zone lines were readily produced by Xylaria polymorpha on Douglas fir, redwood, myrtle, and cottonwood. Blue stain from Scytalidium lignicola was prolific on myrtle and ash. These results indicate that a number of Pacific Northwest native wood species are suitable for controlled spalting, including two conifers. The prevalence of spalting on these wood species should lead to their increased value, and allow the Pacific Northwest to compete within the spalted woods market.

Wood-staining fungal pigments have shown potential use as colorants for wood and textiles, with organic solvents as the pigment carrier. Natural oils have been suggested as an environmentally friendly and more available carrier; however, oils promoted color degradation. The current study examined the mechanism of said degradation and tested therapeutic and food-grade oils (instead of finishing oils) for their potential to carry draconin red, the pigment from Scytalidium cuboideum, without color loss over time. FTIR analysis from finishing oils indicated that oxidation was not likely the cause of color loss as the pigment could not be distinguished from the oils in the IR spectra. SEM was employed to determine if crystal degradation was contributing to color loss and indicated, surprisingly, that the crystals of draconin red formed rather than degraded over time. This suggested crystal breakdown was also not likely the cause of color loss. The pigment did not show degradation in hemp oil, flaxseed oil, and cold-pressed linseed oil when treated with β-carotene. Further in-depth chemical studies are needed to determine the mechanism of color loss in pigmented natural oils; however, food-grade oils appear to be a promising alternative to carry draconin red, without degradation of the color.