SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT

A technique, useful for studying the formation of kiln brown stain in wood drying, has been developed to measure the surface colour change in a single board wood sample during drying. The wood sample is planed carefully in the green state to remove any surface wood that was damaged during cutting. T...

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Main Authors: MC McCurdy, S Pang, R B Keey
Format: Article
Language:English
Published: Universidad del Bío-Bío 2006-01-01
Series:Maderas: Ciencia y Tecnología
Subjects:
Online Access:http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000100004
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author MC McCurdy
S Pang
R B Keey
author_facet MC McCurdy
S Pang
R B Keey
author_sort MC McCurdy
collection DOAJ
description A technique, useful for studying the formation of kiln brown stain in wood drying, has been developed to measure the surface colour change in a single board wood sample during drying. The wood sample is planed carefully in the green state to remove any surface wood that was damaged during cutting. The intact tracheids at the surface cause the evaporative front to remain at the surface during drying and therefore colour formation also occurs right at the surface. In this way, the colour can be measured using a spectrophotometer at various stages during drying without having to slice the sample. Experiments were carried out to measure the change in colour of wood from green to EMC corresponding to the drying schedule used. At the end of each schedule the boards were held at the EMC to determine how the colour changed below fibre saturation point. The results show that the colour of the wood continues to change below the fibre saturation point and the nature of the colour change indicates an increase in the complexity of the coloured compounds present. Further experiments were done to measure the rate of colour development at different temperatures using the technique developed. The results have shown a correlation between temperature and colour development over the range 50°C to 70°C with the rate increasing significantly above 60°C
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spelling doaj.art-dba7f41e770c42e0a932d631016537622022-12-22T03:28:02ZengUniversidad del Bío-BíoMaderas: Ciencia y Tecnología0717-36440718-221X2006-01-01813140SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINTMC McCurdyS PangR B KeeyA technique, useful for studying the formation of kiln brown stain in wood drying, has been developed to measure the surface colour change in a single board wood sample during drying. The wood sample is planed carefully in the green state to remove any surface wood that was damaged during cutting. The intact tracheids at the surface cause the evaporative front to remain at the surface during drying and therefore colour formation also occurs right at the surface. In this way, the colour can be measured using a spectrophotometer at various stages during drying without having to slice the sample. Experiments were carried out to measure the change in colour of wood from green to EMC corresponding to the drying schedule used. At the end of each schedule the boards were held at the EMC to determine how the colour changed below fibre saturation point. The results show that the colour of the wood continues to change below the fibre saturation point and the nature of the colour change indicates an increase in the complexity of the coloured compounds present. Further experiments were done to measure the rate of colour development at different temperatures using the technique developed. The results have shown a correlation between temperature and colour development over the range 50°C to 70°C with the rate increasing significantly above 60°Chttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000100004kiln brown stainwood colourcolour measurementwood drying
spellingShingle MC McCurdy
S Pang
R B Keey
SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
Maderas: Ciencia y Tecnología
kiln brown stain
wood colour
colour measurement
wood drying
title SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
title_full SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
title_fullStr SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
title_full_unstemmed SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
title_short SURFACE COLOUR CHANGE IN WOOD DURING DRYING ABOVE AND BELOW FIBRE SATURATION POINT
title_sort surface colour change in wood during drying above and below fibre saturation point
topic kiln brown stain
wood colour
colour measurement
wood drying
url http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000100004
work_keys_str_mv AT mcmccurdy surfacecolourchangeinwoodduringdryingaboveandbelowfibresaturationpoint
AT spang surfacecolourchangeinwoodduringdryingaboveandbelowfibresaturationpoint
AT rbkeey surfacecolourchangeinwoodduringdryingaboveandbelowfibresaturationpoint