The drawing under study is made in 1868 (as evident from the signature) and the watermark mentions the paper manufacturing year to be 1866. ‘Watermarks’ are markings put into paper during its production, by making thinner or thicker  layer of pulp when it is still wet. It becomes visible when paper seen with light source at the back of the paper. This drawing was created … Continue reading Studying Paper for presence of watermark and bluish tinge: Case of 150 years old drawing