Method for spectroscopically monitoring resin applied to a planar surface of veneer-wood sheets during travel in an assembly line. Spectroscopic instrumentation for monitoring applied resin is calibrated by measurements of predetermined resin applications to reference-test-samples, so as to provide a pre-determined relationship enabling monitoring of applied resin, during commercial production of a veneer-wood product using the visible light spectrum and near infrared extending to 2500 nm. Monitoring of selected radiation absorbance by the applied resin is carried out by spectroscopic measurement of non-absorbed electromagnetic radiation, as reflected back by the wood-veneer matrix; selected wavelengths are utilized for determining average resin-weight per designated surface area of a sheet. Selecting penetrative wavelengths enables use of multiple types of hardwood and softwood for veneer sheets during in-line production, providing for separate calibration for selected wood type and resin combinations measuring instrumentation.