lmpact of UV-rays on stain durability of various wood species

The change of colour is influenced by the type of coat, wood and the period of UV-radiation exposure when indicating the light durability of various woodspecies. Tannin, which may be used along with synthetic stains, when combined with inorganic salts forms complex compounds of different shades of colour. A 3% stilbene fraction of spruce bark water extract, various concentrations of spruce bark water extracts combined with copper (II) chloride and iron (III) chloride, solventborne and waterborne stain were used on 4 different wood species. After a 72-hour-long UV-radiation exposure, the change of colour and durability of stains were compared on various wood species. The change of colour was measured by means of a spectrophotometer. The results include a change of colour in the L*, a*, b* colour system. Stains obtained with 10%, 25% and 40% concentration of spruce bark water extract combined with iron chloride proved to be the most durable in all researched wood species.