Page 11 - InnoRenew CoE International Conference 2023
P. 11
Colour changes in natural and treated wood
Marica Mikuljan ¹*, Andreja Kutnar 1,2, Matthew Schwarzkopf 1,2
1 InnoRenew CoE, Livade 6a, 6310 Izola, Slovenia; marica.mikuljan@innorenew.eu, matthew.schwarzkopf@innorenew.eu,
andreja.kutnar@innorenew.eu
2 Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia
* Corresponding author
Colour, texture, and gloss are among the most important aesthetic properties of wood. Wood discoloration can
affect the natural visual appearance of many wood species and cause significant economic problems in the timber
industry. Natural weathering and accelerated weathering test are two key methods for testing the durability of
materials exposed to different weathering conditions. In most cases, outdoor testing of materials takes too long
to ensure the necessary results before use. Accelerated weathering test provides information on the behaviour
of products when exposed to long-term weathering in a single week.
We investigated the colour change in the ageing of untreated larch and spruce wood in a natural environment
over a period of 18 months, and of spruce and larch wood protected with a transparent finish and a “Palisander”
colour finish for outdoor use using the accelerated weathering test method. The gloss and colour measurements
of the samples were carried out using an Ericksen Easy Co 566 in the CIE L*a*b* colour space. Unprotected wood
shows a different colour after two months of exposure. After 18 months, the measured colour points of spruce
move into the grey zone of the a*b* colour space, while in larch the yellow and red colours are still detectable. In
the protected wood with finishes, the gloss and colour change depend on the combination of the type of finish
and the type of wood. As the material ages, this combination affects the colour difference E*, the displacement
of the points in the a*b* colour space and the gloss.
Keywords: wood, weathering, color measuring, properties
13–14 SEPTEMBER 2023 I IZOLA, SLOVENIA 11
Marica Mikuljan ¹*, Andreja Kutnar 1,2, Matthew Schwarzkopf 1,2
1 InnoRenew CoE, Livade 6a, 6310 Izola, Slovenia; marica.mikuljan@innorenew.eu, matthew.schwarzkopf@innorenew.eu,
andreja.kutnar@innorenew.eu
2 Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia
* Corresponding author
Colour, texture, and gloss are among the most important aesthetic properties of wood. Wood discoloration can
affect the natural visual appearance of many wood species and cause significant economic problems in the timber
industry. Natural weathering and accelerated weathering test are two key methods for testing the durability of
materials exposed to different weathering conditions. In most cases, outdoor testing of materials takes too long
to ensure the necessary results before use. Accelerated weathering test provides information on the behaviour
of products when exposed to long-term weathering in a single week.
We investigated the colour change in the ageing of untreated larch and spruce wood in a natural environment
over a period of 18 months, and of spruce and larch wood protected with a transparent finish and a “Palisander”
colour finish for outdoor use using the accelerated weathering test method. The gloss and colour measurements
of the samples were carried out using an Ericksen Easy Co 566 in the CIE L*a*b* colour space. Unprotected wood
shows a different colour after two months of exposure. After 18 months, the measured colour points of spruce
move into the grey zone of the a*b* colour space, while in larch the yellow and red colours are still detectable. In
the protected wood with finishes, the gloss and colour change depend on the combination of the type of finish
and the type of wood. As the material ages, this combination affects the colour difference E*, the displacement
of the points in the a*b* colour space and the gloss.
Keywords: wood, weathering, color measuring, properties
13–14 SEPTEMBER 2023 I IZOLA, SLOVENIA 11
