C olour of the \vood surface is a m ajör criterion in evaluating the quality of fu rn itu re, panels, door elem ents and flooring. M eam vhile, wood is not isotropic, and the textural quality of the surface affects the visual appearance. O ptical devices using diffuse illum ination com pensate defîciency of illum ination \vith given inclination. Using diffuse illum ination C IE L *a:1:b :|: colour values of different stru ctu ral areas of oak \vood in t\vo directions perpendicular to each other are determ ined. F ib re areas w ere found to be m ore sensitive to sam ple position than ray areas. Also the colour difference values betvveen stru ctu ral areas of oak vvood is g reater than 20. T herefore com parison and segregation of \vood based on colour m easurem ent m ust be m ade carefully.