Reactive (high-solids) finishes cure by chemical reaction and require less build-up (coats) to fill open grain woods. They have less shrinkage than solvent-borne or water-borne "evaporatives" - those that cure by drying. One problem in applying reactives to oily woods is that the natural oils in the woods interfere with the curing of the reactive finishes. Shellac is often used to seal the grains on oily woods but this takes a fair amount of time. Solarez UV-cure grain filler and sealer reacts not by evaporation but by photochemical reaction and does so in seconds, not hours.