Transparent tracing paper for indian ink drawing - treated with nonvolatile organic acid to improve receptivity for slightly alkaline ink

摘要

Transparent tracing paper for Indian ink drawings is improved by treating its surface in such a manner that its pH is shifted into the acid range. The acidification of the surface of a tracing paper improves its receptivity for the slightly alkaline Indian ink, so that its covering power is increased. The acidification of the paper is conveniently carried out by adding to the sizing compsn. a non-volatile, carboxylic, dicarboxylic or hydroxydicarboxylic acid, esp. sulphosalicylic, succinic, tartaric, adipic or citric acid, or an aromatic sulphonic acid, esp. benzenesulphonic acid. The acid should be added to the size in such an amt. that after drying there remains lg. of the acid per m2 of the paper.