Wood colour of central European wood species: CIELAB characterisation and colour intensification

Meints, Tillmann; Teischinger, Alfred; Stingl, Robert; Hansmann, Christian

doi:10.1007/s00107-016-1108-0

Cited by 34 publications

(16 citation statements)

References 16 publications

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“…Internal reflection accentuates the effect of spectral variations and results in hue as well as color saturation changes (Dorsey et al 2008). Meints et al (2017) stated that for central European wood species, those with darker color and high chroma or hue are highly susceptible to color intensification due to wetting. Likewise, Senthilkumar et al (2011) stated that the increase in chroma of dyed cotton fabric was paralleled with higher RH, and a change in intensity was dependent on dye color and its concentration.…”

Section: Chromaticity and Overall Color Changesmentioning

confidence: 99%

Color Changes of Various Wood Species in Response to Moisture

Baar¹,

Paschová²,

Čermák³

et al. 2019

WFS

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Color including texture and gloss is one of the most important esthetical attributes of wood. For any porous materials in contact with water, the phenomenon of surface darkening arises from a change in the refractive index, as water enters air-filled pores. For the first time, this research investigated to what extent MC differences affect the surface color, below fiber saturation and after the pores are filled with water, with respect to extractive contents. Samples from 13 wood species were exposed to various climates, and as soon as EMC was reached, the color was determined. Color changes were also recorded after water submersion and also after vacuum impregnation in water. Chromaticity parameters a* and b* widely increased, along with higher moisture contents. Lightness changes were mostly stable at lower moisture contents. An exception was demonstrated by the heartwood species black locust, plum, walnut, and oak, which showed a brightening effect at lower moisture contents, followed by the darkening phase. The overall darkening of wood at high RH is connected to capillary condensation. Liquid water present in the cell lumen most caused darkening and an intensification of hue (increase in a* and b*). Darkening was even more expressed after vacuum impregnation with water. In conclusion, with only limited fluctuations in moisture contents below fiber saturation, the expected color changes are minor to neglectable.

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Section: Chromaticity and Overall Color Changesmentioning

confidence: 99%

Color Changes of Various Wood Species in Response to Moisture

Baar¹,

Paschová²,

Čermák³

et al. 2019

WFS

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“…A técnica de colorimetria, que consiste em determinar a cor de uma superfície por meio de espectrofotômetros e colorímetros, tem sido aplicada à madeira para caracterizar seus parâmetros colorimétricos, avaliar os efeitos de tratamentos termomecânicos na coloração da madeira e avaliar infestações patológicas (AMORIM;CAMARGOS, 2013;ZANUNCIO et al, 2014;CADEMARTORI et al, 2014;BARCÍK;GASPARÍK;RAZUMOV, 2015;POUBEL et al, 2015;MEINTS et al, 2016;LAZAROTTO et al, 2016). É uma técnica de simples aplicação, podendo ser empregada na pré-classificação a partir do desdobro da tora, na qualificação das peças e na formação de banco de dados (BARROS; MUNIZ; MATOS, 2014).…”

Section: Introductionunclassified

Estimativa da resistência e da rigidez à compressão paralela às fibras da madeira de Pinus sp. pela colorimetria

Marini

Almeida

et al. 2021

Ambient. constr.

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Resumo Propriedades de resistência e de rigidez da madeira, fundamentais em um projeto estrutural, são determinadas com base em ensaios mecânicos. Entre as propriedades mecânicas da madeira, destacam-se as de resistência (fc0) e de rigidez (Ec0) à compressão na direção paralela às fibras. A cor é uma característica própria de cada espécie. Se determinadas experimentalmente as propriedades fc0 e Ec0 de uma espécie de madeira com base em um significativo número de amostras caracterizadas, a correlação dessas propriedades por meio de equações obtidas por regressão possibilita realizar estimativas de tais propriedades sem a necessidade de novos ensaios, procedimento esse com potencial de aplicação por empresas madeireiras. Com o auxílio do sistema CIE L*a*b* e de 403 peças de madeira de Pinus sp., equações obtidas por modelo de regressão foram utilizadas para a estimativa do Ec0 e da fc0 em função dos parâmetros colorimétricos e do número de anéis de crescimento. Da estimativa do Ec0 (R2 = 43,61%), pela ANOVA da equação de regressão foi constatada significância apenas do número de anéis de crescimento (Nle). Para a resistência à compressão paralela às fibras (R2 = 48,53%), apenas os parâmetros colorimétricos e as interações desses parâmetros afetaram significativamente a fc0.

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“…The CIE 1976 L * a * b * colour system also allows visualisation of the cylindrical parameters of wood, the colour saturation-chromaticity (C * ab ) and the hue tone angle (h ab ) [6]. The tropical wood species occupy a much greater portion of the colour space in comparison with temperate (for example European) species [7,8].…”

Section: Introductionmentioning

confidence: 99%

The Colour of Tropical Woods Influenced by Brown Rot

Vidholdová

Reinprecht

2019

Forests

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Interesting aesthetic properties of tropical woods, like surface texture and colour, are rarely impaired due to weathering, rotting and other degradation processes. This study analyses the colour of 21 tropical woods before and after six weeks of intentional attack by the brown-rot fungus Coniophora puteana. The CIEL*a*b* colour system was applied for measuring the lightness, redness and yellowness, and from these parameters the hue tone angle and colour saturation were calculated. Lighter tropical woods tended to appear a less red and a more yellow, and had a greater hue tone angle. However, for the original woods was not found dependence between the lightness and colour saturation. Tropical woods at attack by C. puteana lost a weight from 0.08% to 6.48%. The lightest and moderately light species—like okoumé, iroko, ovengol and sapelli—significantly darkened, while the darkest species—wengé and ipé—significantly lightened. The majority of tropical woods obtained a brighter shade of yellow, typically wengé, okoumé and blue gum, while some of them also a brighter shade of green, typically sapelli, padouk and macaranduba. C. puteana specifically affected the hue tone angle and colour saturation of tested tropical woods, but without an apparent changing the tendency of these colour parameters to lightness. The total colour difference of tested tropical woods significantly increased in connection with changes of their lightness (ΔE*ab = 5.92 − 0.50·ΔL*; R2 = 0.37), but it was not influenced by the red and yellow tint changes, and weight losses.

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Wood colour of central European wood species: CIELAB characterisation and colour intensification

Cited by 34 publications

References 16 publications

Color Changes of Various Wood Species in Response to Moisture

Color Changes of Various Wood Species in Response to Moisture

Estimativa da resistência e da rigidez à compressão paralela às fibras da madeira de Pinus sp. pela colorimetria

The Colour of Tropical Woods Influenced by Brown Rot

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