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The purpose of this study was to investigate the contribution of Caesalpinia sappan (sappan wood) bark extractives by analyzing color change of the bark after extraction and the color of the extracts with several color measurement methods. Successive extraction was performed with n-hexane, ethyl acetate, methanol, and hot water. Color change of the bark was measured using CIELab color system and the extracts were analyzed with Ultraviolet-Visible Spectrophotometer, total phenolic content (TPC), and Gas Chromatography Mass Spectrometry (GC-MS). The results showed that the highest change on the bark color after methanol extraction with the Δa* and Δb* values of -2,53 ± 0,60 and -3,64 ± 1,20 respectively. Also, methanol extract showed the highest total phenolic content (860,24 ± 30,19 mg GAE/g). In addition, the Ultraviolet-Visible is analysis showed a peak at 478 nm in the hot-water soluble extract and two peaks in the methanol soluble extract at 396 nm and 478 nm. Hydroquinone was detected as one of the major compounds by Gas Chromatography Mass Spectrometry in the methanol soluble extract. It was suggested that the color of Caesalpinia sappan (sappan wood) bark as well as the deep red coloration of its extract might be contributed by multiple phenolic compounds contained in the methanol extract with hydroquinone as its precursor. Therefore, it is also a potential source for coloring matter.

The purpose of this study was to investigate the contribution of Caesalpinia sappan (sappan wood) bark extractives by analyzing color change of the bark after extraction and the color of the extracts with several color measurement methods. Successive extraction was performed with n-hexane, ethyl acetate, methanol, and hot water. Color change of the bark was measured using CIELab color system and the extracts were analyzed with Ultraviolet-Visible Spectrophotometer, total phenolic content (TPC), and Gas Chromatography Mass Spectrometry (GC-MS). The results showed that the highest change on the bark color after methanol extraction with the Δa* and Δb* values of -2,53 ± 0,60 and -3,64 ± 1,20 respectively. Also, methanol extract showed the highest total phenolic content (860,24 ± 30,19 mg GAE/g). In addition, the Ultraviolet-Visible is analysis showed a peak at 478 nm in the hot-water soluble extract and two peaks in the methanol soluble extract at 396 nm and 478 nm. Hydroquinone was detected as one of the major compounds by Gas Chromatography Mass Spectrometry in the methanol soluble extract. It was suggested that the color of Caesalpinia sappan (sappan wood) bark as well as the deep red coloration of its extract might be contributed by multiple phenolic compounds contained in the methanol extract with hydroquinone as its precursor. Therefore, it is also a potential source for coloring matter. [ABSTRACT FROM AUTHOR]

En el presente trabajo se determinaron los parámetros colorimétricos mediante el sistema CIELAB y la densidad aparente por densitometría de rayos X en madera de Guazuma crinita para obtener información de su calidad en el uso como madera solida o transformada. La evaluación se realizó en tres niveles del eje axial (basal, medio y apical) de una plantación de 5 y 8 años, en la zona de Puerto Inca, departamento de Huánuco, Perú. En ambas edades, empleando el sistema CIElab, se encontró que la madera es de coloración homogénea y se clasifica como rosa grisáceo. La densidad aparente medida por densitometría de rayos X en el sentido médula - corteza fue de 0,52 g/cm3 y 0,56 g/cm3 para 5 y 8 años respectivamente; con promedios mayores en el nivel basal (5 años: 0,65; 8 años:0,68) y menores en el nivel apical (5 años: 0,43; 8 años: 0,47). Los perfiles densitométricos mostraron, en general, que radialmente hay un aumento de la densidad aparente en el sentido médula - corteza. La densidad de la madera madera de 5 años resultó más uniforme que la de 8 años con un índice de uniformidad de 149,7 y 170,3, respectivamente.

El objetivo de este trabajo fue describir el color del tallo, también conocido como culmo, de Guadua angustifolia con el sistema colorimétrico CIE-L*a*b* y analizar la variabilidad entre los tres estados de madurez (joven, maduro y sobremaduro). El material de estudio se recolectó en la plantación de la empresa AGROMOD, ubicada en Reforma, Chiapas, México. Se tomaron 12 culmos de dos, cuatro y seis años, 36 en total, y se midió el color utilizando los parámetros del sistema CIE-L*a*b* con ayuda de un colorímetro digital. Posteriormente, se utilizó la metodología propuesta por CIE 2004 para obtener la variación total de color (∆E*) y medir la magnitud de la diferencia del color entre los tres estados de madurez. Como consecuencia de la madurez se observó un cambio secuencial de coloración en la parte externa del culmo, desde un verde claro, verde grisáceo, gris, hasta un tono café. Los valores de ∆E* fueron mayores de 20, lo que de acuerdo a los criterios de percepción de diferencia de color ∆E* indica que la variación del color entre un estado de madurez y otro puede clasificarse como “Muy grande”. Asimismo, al realizar un análisis de Kruskal Wallis en las coordenadas CIE-L*a*b* se encontró que la diferencia del color por edad es estadísticamente significativa (p < 0,05).

Organic substances have been used for different wood treatments, especially impregnation procedures, aiming to improve certain wood properties. The objective of this study was to evaluate dimensional stability and colorimetric features for a mature pine wood (Pinus elliottii) impregnated by vacuum-pressure process with variable concentrations (10 wt%, 25 wt% and 50 wt%) of furfuryl alcohol (using ethyl alcohol as catalyst). The wood samples were characterized for: linear shrinkages, linear swellings, shrinkage anisotropy, swelling anisotropy, as well as colorimetric parameters (following the CIELab method). The impregnation with furfuryl alcohol increased the dimensional stability of the studied pine wood and the treatment with 50 wt% of furfuryl alcohol stood out based on these results. Regarding the colour patterns, there were changes in the final colorimetric appearances of the treated wood samples, which acquired darker and reddish colours when compared to the pristine group. The treatment with 50 wt% furfuryl alcohol again was responsible for the highest colour change and, because of that, may be indicated for solid wood products with high added value.

El objetivo de este trabajo fue describir el color del tallo, también conocido como culmo, de Guadua angustifolia con el sistema colorimétrico CIE-L*a*b* y analizar la variabilidad entre los tres estados de madurez (joven, maduro y sobremaduro). El material de estudio se recolectó en la plantación de la empresa AGROMOD, ubicada en Reforma, Chiapas, México. Se tomaron 12 culmos de dos, cuatro y seis años, 36 en total, y se midió el color utilizando los parámetros del sistema CIE-L*a*b* con ayuda de un colorímetro digital. Posteriormente, se utilizó la metodología propuesta por CIE 2004 para obtener la variación total de color (ΔE*) y medir la magnitud de la diferencia del color entre los tres estados de madurez. Como consecuencia de la madurez se observó un cambio secuencial de coloración en la parte externa del culmo, desde un verde claro, verde grisáceo, gris, hasta un tono café. Los valores de ΔE* fueron mayores de 20, lo que de acuerdo a los criterios de percepción de diferencia de color ΔE* indica que la variación del color entre un estado de madurez y otro puede clasificarse como "Muy grande". Asimismo, al realizar un análisis de Kruskal Wallis en las coordenadas CIE-L*a*b* se encontró que la diferencia del color por edad es estadísticamente significativa (p < 0,05). The aim of this study was to describe the Guadua angustifolia stelm (culm) color with the CIE-L*a*b* color system and to analyze the color variation among the three stages of maturity (young, mature and overripe). The study material was collected from the AGROMOD plantation, located in Reforma, Chiapas in Mexico. Twelve culms of two, four and six years were taken, 36 in total, and the color was measured using the CIE-L * a * b * system parameters by using a digital colorimeter. Then, with the methodology proposed by the CIE 2004, the total color variation (ΔE*) and the magnitude of the color difference between the three maturity stages were obtained. As a consequence of maturity, a sequential change in coloration was observed in the outer part of the culm, going from light green, greyish green, grey to brown. The ΔE* values were greater than 20, which according to the perception of color difference criteria, indicates that the color variation between one stage of maturity and another can be classified as "Very large". Also, when performing an analysis of variance in the CIE-L*a*b* coordinates, it was found that the difference in color by age is statistically significant (p < 0,05). [ABSTRACT FROM AUTHOR]

Organic substances have been used for different wood treatments, especially impregnation procedures, aiming at improve certain wood properties. The objective of this study was to evaluate dimensional stability and colourimetric features for a mature pine wood (Pinus elliottii) impregnated by vacuum-pressure process with variable concentrations (10 wt%, 25 wt% and 50 wt%) of furfuryl alcohol and using ethyl alcohol as catalyst. The wood samples were characterized for:linear shrinkages, linear swellings, shrinkage anisotropy, swelling anisotropy, as well as colorimetric parameters (following the CIELab method). The impregnation with furfuryl alcohol increased the dimensional stability of the studied pine wood and the treatment with a concentration of 50 wt% stood out based on these results. Regarding the colourpatterns, there were changes in the final colorimetric appearances of the treated wood samples, which acquired darker and reddish colours when compared to the pristine group. The treatment with 50 wt% of furfuryl alcohol also was responsible for the highest colour change and, because of that, may be indicated for solid wood products with high added value. [ABSTRACT FROM AUTHOR]

El algarrobo blanco (Prosopis alba) se caracteriza por sus excelentes propiedades física-mecánicas en su madera, lo cual la hace muy apreciable en la industria del mueble. El color es un rasgo importante en ciertos usos de la madera, e incide en su calidad. El objetivo de este trabajo fue evaluar la variación colorimétrica de la madera entre sitios, sección y región de la madera y correlacionar parámetros colorimétricos con rasgos dentrométricos del árbol. Las muestras se extrajeron de tres rodales naturales (Los Arias, Santiago del Estero; Isla Cuba, Formosa y Villa Ángela, Chaco) y una plantación (San Isidro, Santiago del Estero), de la Región Chaqueña Argentina. Los parámetros colorimétricos (L*, a*, b*) se obtuvieron con un espectrofotómetro KONICA MINOLTA CM-5 con iluminante D65. El análisis confirmó que existen diferencias significativas en parámetros colorimétricos entre sitios, secciones y regiones de las muestras de madera analizadas. El tamaño de los árboles se encuentra directamente relacionado con los parámetros colorimetricos. The algarrobo blanco (Prosopis alba) is characterized by its excellent physical-mechanical properties in its wood. The colour is an important feature in certain use of wood, and affects its quality. The objective of this work was to evaluate the colorimetric variation between sites, section and region of the wood samples and correlate colorimetric parameters with dentrometric features of the tree. The samples were obtained from three natural stands (Los Arias, Santiago del Estero, Isla Cuba, Formosa and Villa Ángela, Chaco) and a plantation (San Isidro, Santiago del Estero), in the Chaqueña region of Argentina. The colorimetric parameters (L *, a *, b *) were obtained with a KONICA MINOLTA CM-5 spectrophotometer with illuminant D65. The colorimetric analysis confirmed that there are significant differences in colorimetric parameters between sites, section and region in the wood samples analyzed. The size of the trees is directly related to the colorimetric parameters.

The algarrobo blanco (Prosopis alba) is characterized by its excellent physical-mechanical properties in its wood. The colour is an important feature in certain use of wood, and affects its quality. The objective of this work was to evaluate the colorimetric variation between sites, section and region of the wood samples and correlate colorimetric parameters with morphometric features of the tree. The samples were obtained from three natural stands (Los Arias, Santiago del Estero, Isla Cuba, Formosa and Villa Ángela, Chaco) and a plantation (San Isidro, Santiago del Estero), in the Chaqueña region of Argentina. The colorimetric parameters (L*, a*, b*) were obtained with a Konica Minolta CM-5 spectrophotometer with illuminant D65. The colorimetric analysis confirmed that there are significant differences in colorimetric parameters between sites, section and region in the wood samples analyzed. The size of the trees is directly related to the colorimetric parameters. [ABSTRACT FROM AUTHOR]

Vochysia guatemalensis has been planted over large tropical areas to obtain lumber products. However, compared with naturally-grown material variations in wood color have been noted. In the current research, trees from two 8-year-old fast-grown plantations were sampled from different climatic conditions in order to identify the causes of color variation. The study evaluated the heartwood presence, grain pattern, distance from pith, height within the tree, and effect of drying schedules. The wood color was measured by CIEL*a*b* systems.Wood color of Vochysia guatemalensis is a combination of different tonalities of lightness (L*), redness (a*), and yellowness (b*), however, the lightness and yellowness components were the dominant tones. The color of heartwood and sapwood were different before and after drying. A negative relationship was found between a* and L*, and a* and b* in the undried state, but no relationship was found between L* and b*. The L* index is only correlated with heartwood presence in undried wood. In dried wood, only a relationship between a* and L* is maintained, while other color parameters were affected by climate, drying schedule and heartwood presence, the L* parameter being the most affected. The dried wood displays a lighter surface than the wood before drying. The variations in the dried wood suggest that it is useful to establish dried lots of lumber according to the drying schedule, source and presence of sapwood and heartwood.La especie Vochysia guatemalensis ha sido plantada sobre largas áreas en regiones tropicales. Así mismo, han sido observadas grandes variaciones del color de su madera. En la investigación fueron muestreadas plantaciones de 8 años de edad en diferentes condiciones de clima con el fin de establecer las causes de variación de la madera. Fueron evaluadas la presencia de duramen, el patrón de aserrío, la distancia de la medula y el programa de secado. El color fue medido por el sistema CIELab. Fue encontrado que la madera de V. guatemalensis presenta una combinación de tonalidades de claros (L*), rojos (a*) y amarrillos (b*), siendo los colores claros y amarrillos los tonos dominantes. El color del duramen y la albura fueron diferentes antes y después del secado. Una negativa correlación entre a* y L*, y a* y b* fue encontrada, pero ninguna correlación fue observada entre L* y b*. El índice L* fue el único parámetro correlacionado con el duramen en madera verde. En la madera seca, solamente se mantuvo la relación a* y L*, mientras que los parámetros del color fueron afectados por el clima, programa de secado y duramen, siendo L* el más afectado. La madera seca presentó una superficie más clara que la madera antes del secado. Las variaciones en madera seca sugieren la conveniencia de establecer lotes de secado de acuerdo al programa de secado aplicado, procedencia y presencia de albura y duramen.

In this paper the effect of heat and ammonia treatment on the change in colour of oak wood (Quercus robur) and comparison of physical and mechanical properties were investigated. Wood specimens were made from heartwood and sapwood in dimensions 30×30×30 mm3. The specimens were subjected to heat treatment at 180ºC and 230ºC for 2 and 4 hours, others were treated by ammonia for 24 hours. After these processes, CIELAB colour, hardness, EMC, density and MOE of wood were tested in comparison with untreated samples. The results show that the heat treatment contributed to darkening of sapwood and heartwood and the total colour change increased up to 38.47 units (CIELAB) in the radial direction and 37.75 units (CIELAB) in the tangential direction. Previous research into ammonia treatment shows that the most significant changes were noticed after 1 day. The colour changes between sapwood and heartwood were more noticeable in ammonia treatment than in the case of heat treatment. All other observed properties were decreased in the case of heat treatment. Ammonia treatment does not have a significant influence on the other observed properties. The results proved that ammonia treatment is a modification that improves the decorative value but has a minimal effect on technologically relevant properties of solid wood. Nevertheless, the heat treatment can be used as comparable process for colour change of wood.

In this paper the effect of heat and ammonia treatment on the change in colour of oak wood (Quercus robur) and comparison of physical and mechanical properties were investigated. Wood specimens were made from heartwood and sapwood in dimensions 30x30x30 mm³. The specimens were subjected to heat treatment at 180°C and 230°C for 2 and 4 hours, others were treated by ammonia for 24 hours. After these processes, CIELAB colour, hardness, EMC, density and MOE of wood were tested in comparison with untreated samples. The results show that the heat treatment contributed to darkening of sapwood and heartwood and the total colour change increased up to 38.47 units (CIELAB) in the radial direction and 37.75 units (CIELAB) in the tangential direction. Previous research into ammonia treatment shows that the most significant changes were noticed after I day. The colour changes between sapwood and heartwood were more noticeable in ammonia treatment than in the case of heat treatment. All other observed properties were decreased in the case of heat treatment. Ammonia treatment does not have a significant influence on the other observed properties. The results proved that ammonia treatment is a modification that improves the decorative value but has a minimal effect on technologically relevant properties of solid wood. Nevertheless, the heat treatment can be used as comparable process for colour change of wood. [ABSTRACT FROM AUTHOR]

Vochysia guatemalensis has been planted over large tropical areas to obtain lumber products. However, compared with naturally-grown material variations in wood color have been noted. In the current research, trees from two 8-year-old fast-grown plantations were sampled from different climatic conditions in order to identify the causes of color variation. The study evaluated the heartwood presence, grain pattern, distance from pith, height within the tree, and effect of drying schedules. The wood color was measured by CIEL*a*b* systems. Wood color of Vochysia guatemalensis is a combination of different tonalities of lightness (L*), redness (a*), and yellowness (b*), however, the lightness and yellowness components were the dominant tones. The color of heartwood and sapwood were different before and after drying. A negative relationship was found between a* and L*, and a* and b* in the undried state, but no relationship was found between L* and b*. The L* index is only correlated with heartwood presence in undried wood. In dried wood, only a relationship between a* and L* is maintained, while other color parameters were affected by climate, drying schedule and heartwood presence, the L* parameter being the most affected. The dried wood displays a lighter surface than the wood before drying. The variations in the dried wood suggest that it is useful to establish dried lots of lumber according to the drying schedule, source and presence of sapwood and heartwood. [ABSTRACT FROM AUTHOR]