The significantly higher changes in L for the digital
images could be caused by glossiness or the increasing
unevenness of the product surface, more likely a combination
of the two. In the initial phase of the drying process although not visually identifiable, the glossiness of the surface
due to water reflecting the light may have resulted in
values that were higher than the values of the actual surface.
As soon as the surface water had evaporated, this
influence was eliminated. Furthermore, the increasing
unevenness of the surface due to shrinkage might have
caused heterogeneity in light distribution on the surface
of the sample