Indonesia is an archipelago where most of Indonesia is widespread
throughout the oceans. Indonesia therefore has the potential for a great sea
include biological resources, mineral, and energy. With the potential of the
sea then we can use it for recreation and marine scientific investigations.
23.5.13
NATURAL COLOUR OF WOOD (Part III)
Natural color of wood can change rapidly due to several causes, either by extractive substances contained therein as well as by influences from outside the timber. Examples of mahogany (Swietenia macrophylla) the color changed from pink or light red to red brown quickly on a piece of wood fresh. This color change can lead to defects in the wood color defects. Another term often used is the discoloration.
Discoloration is caused by defective color color changes which occur in wood caused by a variety of treatment without giving the dye. There are five factors that cause the occurrence of staining, namely: the influence of temperature and humidity, the process of oxidation, deposition of pigment on the surface of the wood, the influence of the organism and in contact with metal.
The color of wood exposed to the atmosphere often darken the wood and sapwood usually be darker than the wood paneling. These changes usually occur in the natural chemical produced by the oxidation reactions of organic components contained in the wood.
The color change can occur immediately after trees felled in the forest or wet after sawing logs into boards. Alder wood quickly changed color from whitish to reddish, then fade to brown. Black locust wood porch changed from light green to dark brown, while the Douglas fir becomes reddish.
Further stated also that the old wood exposed to sunlight, especially in the high plains, changing its color to brown. While prolonged exposure to rain or high humidity change the color of the wood becomes dark gray.
Discoloration on teak (Tectona grandis Lf) caused by the oxidation process of extractive substances in the wood. As well as the study of sugi wood (Cryptomeria japonica). From some research it is known that the use of high temperatures in the drying of wood has caused the color change. This is caused by the discharge of extractive substances contained in the timber to the surface. As for the wood white or light colored wood and the sapwood, the changes can be caused by fungal attack. Wood is attacked is usually a blue or black. Generally, the wood was attacked while still in fresh condition with a high water content.
THE END
13.5.13
NATURAL COLOUR OF WOOD (Part II)
Wood
from older trees may have older color (darker) when compared with the wood from younger trees of the same type. Dry wood in different colors when compared with the color of wet wood. Wood that has been stored in the open color can be darker or lighter than fresh wood, this depends on the circumstances (weather, wind, light, and so on). In general, the color of a particular type of wood is not a pure color, but color is a mixture of several kinds of colors, so that in appearance it is difficult to be expressed precisely in words.
As
the Giver
of Extractive Substances Natural Color Wood
The color of wood caused by a material that can be extracted, which are called extractive. Extractive is a chemical in a timber that can be dissolved in a neutral solvent such as water, ether, alcohol, benzene and acetone. The content of extractive in wood varies from less than 1% to more than 10% and can reach 20% for tropical timber. Each type of tree contains one or several kinds of extractive substances and only a few species of trees that contain all extractive substances.
Flavonoids, stilbena, tannins and anthocyanins is a class of dye wood extractive. Flavonoids are compounds that cause the wooden porch of red, yellow, brown or blue. Polyphenols and tannins in the wood broad leaves have a great contribution to the color of wood, especially wooden color terraces and in the past few broad leaves of wood used as dyes. Phenolic contained in a wooden porch, and a little skin in the xylem has a function as a fungicide and in addition it also serves to enhance the staining of wood.
Extractive substances is influenced by growth conditions. For example, differences in walnut color from different geographical locations, related to soil properties. Extractive chemical differences allow to distinguish between types of wood or made of wood staining colorless terrace with the application of chemical substances. Some of the wood such as black locust, honey locust and some tropical wood species have fluorescent for extractive substances.
The color of wood caused by a material that can be extracted, which are called extractive. Extractive is a chemical in a timber that can be dissolved in a neutral solvent such as water, ether, alcohol, benzene and acetone. The content of extractive in wood varies from less than 1% to more than 10% and can reach 20% for tropical timber. Each type of tree contains one or several kinds of extractive substances and only a few species of trees that contain all extractive substances.
Flavonoids, stilbena, tannins and anthocyanins is a class of dye wood extractive. Flavonoids are compounds that cause the wooden porch of red, yellow, brown or blue. Polyphenols and tannins in the wood broad leaves have a great contribution to the color of wood, especially wooden color terraces and in the past few broad leaves of wood used as dyes. Phenolic contained in a wooden porch, and a little skin in the xylem has a function as a fungicide and in addition it also serves to enhance the staining of wood.
Extractive substances is influenced by growth conditions. For example, differences in walnut color from different geographical locations, related to soil properties. Extractive chemical differences allow to distinguish between types of wood or made of wood staining colorless terrace with the application of chemical substances. Some of the wood such as black locust, honey locust and some tropical wood species have fluorescent for extractive substances.
Color As One Of Wood Identification Tool
To know the properties of wood can be used either coarse (macroscopic properties) as well as structural properties (microscopic properties). Included in this is the rough nature of color, luster, smell, taste, texture, fiber and figures. While the nature of the observed structure consisting of pores, parenchyma, the radius, inter cellular channels, lymph channels, and skin inserted. Physical properties can be determined directly by the senses without having to use the tools on the contrary nature of the structure usually use aids in the form of a magnifying glass with magnification of 10 times.
Colors characterize the various types of wood, but it is a trait that is difficult to describe with words. In one species there may be differences and changes due to exposure or as a treatment. Usually the color is expressed visually, but can also be measured technically.
If we want to use color for identification, then the color used is wood paneling. Wood color sapwood usually less real or less typical, so less is diagnostic for the introduction of wood. The color of wood into a value that is important for identification. For example, ebony wood has the typical black color. To determine the exact color can be used Spectrophotometer instrument. This tool can reflect light from a number of different wood surfaces using ultraviolet light.
Further stated also that often there is a striking range of colors, followed by a variety of other colors, so it is difficult to split up individually. Due to the nature of color is easily changeable, then the use of wood in the identification of a secondary color, so it should be used with caution.
To know the properties of wood can be used either coarse (macroscopic properties) as well as structural properties (microscopic properties). Included in this is the rough nature of color, luster, smell, taste, texture, fiber and figures. While the nature of the observed structure consisting of pores, parenchyma, the radius, inter cellular channels, lymph channels, and skin inserted. Physical properties can be determined directly by the senses without having to use the tools on the contrary nature of the structure usually use aids in the form of a magnifying glass with magnification of 10 times.
Colors characterize the various types of wood, but it is a trait that is difficult to describe with words. In one species there may be differences and changes due to exposure or as a treatment. Usually the color is expressed visually, but can also be measured technically.
If we want to use color for identification, then the color used is wood paneling. Wood color sapwood usually less real or less typical, so less is diagnostic for the introduction of wood. The color of wood into a value that is important for identification. For example, ebony wood has the typical black color. To determine the exact color can be used Spectrophotometer instrument. This tool can reflect light from a number of different wood surfaces using ultraviolet light.
Further stated also that often there is a striking range of colors, followed by a variety of other colors, so it is difficult to split up individually. Due to the nature of color is easily changeable, then the use of wood in the identification of a secondary color, so it should be used with caution.
To be continued....
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