The more lignin that's removed, the longer the paper will remain white. But newspaper — which is made cheaply — has more lignin in it than a typical textbook page, so it turns a yellow-brown color faster than other types of paper, she said. Sign up for the Live Science daily ...
By allowing paper and books to start drying instead of freezing, additional damage is occurring to the documents. The escaping water molecules separate and break the paper fibers while rendering the lignin useless. Paper generally swells about 25% greater in volume and 30% or greater in reduced ...