2.2.3. Light microscopy and scanning electron microscopy
For light microscopy (LM), small pieces containing glue line
between maple fancy veneer and plywood were hand sectioned
with a sharp razor blade to minimize artificial cell distortions
by sectioning with a microtome. The sections were stained with
Sudan 4 and toluidine blue to enhance the contrast between the
glue line and the wood, respectively, prior to observation with
the microscope (DW-BM, Korea) with photo camera. For scanning
electron microscopy (SEM), small blocks containing glue line between
fancy veneer and plywood were prepared using a sharp razor
blade. The blocks were air-dried, mounted on stubs with an
adhesive carbon tape, and then coated with gold particles in a
vacuum evaporator. The coated samples were observed with a
SIRIOM SEM (FEI Co.) using a backscattered detector to enhance
the contrast between the glue line and the wood (Kim et al.,
2007b).