The influence of stilbene whitening agents on paper resistance to ageing

The authors examined the influence of stilbene optic whitening agents on paper resistance to ageing, which shows itself in reversion of whiteness and deterioration in strength properties. The white colour and strength properties of papers whitened optically with stilbene derivatives are reduced rapidly under daylight and/or heat. Therefore, it is not advisable to use them in so-called durable papers intended for documentary, cultural and historical purposes, where paper resistance to ageing should be unlimited.