Visuo-tactile and topographic characterizations of finished wood surface quality by French consumers and industrials: acceptability thresholds for raised grain

Abstract

& Key message Raised grain occurring on wood surfaces after the application of a waterborne varnish was felt by human touch because of protruding peaks and a certain amount of materials in the core of the roughness profile. This tactile sensation was correlated with specific roughness parameters. Characteristics of a finished surface quality that is acceptable to consumers were determined. & Context Raised grain occurs on wood surfaces after the application of a waterborne varnish and forces manufacturers to sand the surfaces between coats. Actually, little research has characterised this phenomenon and no techniques have been discovered to avoid its occurrence. & Aims This study aims to identify the topographic parameters that explain the visuo-tactile sensation of raised grain and to define a finished surface quality acceptable to consumers and industry. & Methods Oak (Quercus robur L.) and beech (Fagus sylvatica L.) wood surfaces were planed and sanded in order to have various levels of raised grain. Visuo-tactile analyses were carried out on surfaces having received one coat of varnish to characterise raised grain and having two coats to characterise the acceptable finished surface quality without sanding. Topographic parameters were measured on each type of varnished surface and correlated with the visuo-tactile scores. & Results Raised grain was characterised by the visuo-tactile sensation of protruding peaks and a certain amount of material in the core of the roughness profile for both wood species. Industrials overestimated the surface quality required by consumers. Thresholds of topographic parameters were determined to define acceptable finished surface quality. & Conclusion These findings allowed objective criteria to be defined for describing raised grain and to help industries to optimise their wood machining and finishing processes.

Perceptions of wooden interior product quality – insights on sustainability views among Finnish consumers

“…In addition, there is also evidence that the use of wood in housing construction affects homeowners' perceptions of their identities (Ridoutt et al 2005). Especially with respect to the visual and tactile properties of wood, it has been found that consumers prefer smooth surfaces in particular (De Morais and Pereira 2015;Ramanakoto et al 2017;Ramanakoto et al 2019), and that by using vision and touch they are capable of distin-guishing natural wood from artificial materials (Overlievt and Soto-Faraco 2011). Yet, although consumers have been found to appreciate the naturalness of wood in the home environment (Jonsson et al 2008;Nyrud and Bringslimark 2010;Bhatta et al 2017;Moresová et al 2019), this does not necessarily lead to sustainable purchasing behavior.…”

The perceived quality of wooden building materials—A systematic literature review and future research agenda

“…In the results, consumers preferred a homogeneous visual appearance and moderate color intensity in the case of wooden deck materials (Nyrud et al, 2008); furthermore, they preferred wood with fewer knots over wood with many knots (Nyrud & Bringslimark, 2010). Tactile properties, such as smoothness (Berger et al, 2006;Bhatta et al, 2017;Jonsson et al, 2008;Lindberg et al, 2013;De Morais & Pereira, 2015;Ramanakoto et al, 2019), roughness (Bhatta et al, 2017;Lindberg et al, 2013;De Morais & Pereira, 2015), and vibration (Negreira et al, 2015;Viholainen et al, 2020) were identified. Several studies concluded that consumers preferred smooth surfaces (Bhatta et al, 2017;De Morais & Pereira, 2015;Ramanakoto et al, 2019), and wood was seen as a soft and warm material (Strobel et al, 2017;Viholainen et al, 2020).…”