Table 2.
Color change(ΔE*) of the three wood species after heat treatment
ΔE* value (Classification according to N.B.S.)
Condition
Royal paulownia
Suwon silver poplar
Korean red pine
Control
-
-
-
160°C
1.26
(slight)
5.21
(appreciable)
4.51
(appreciable)
180°C
5.21
(appreciable)
3.28
(appreciable)
3.87
(appreciable)
200°C
21.23
(very much)
29.11
(very much)
43.52
(very much)
220°C
40.62
(very much)
40.47
(very much)
36.99
(very much)