# Watermarks > Continuing my series on digitising ancient manuscripts. Today: watermarks, how they reveal where paper came from, and why beta radiography is the best way to detect them. - Canonical page: https://shorin.me/en/blog/2024/06/watermark/ - Page language: English - Published: 2024-06-26 - Tags: BibliotecaApostolicaVaticana, Preservation, Library, Book - Russian version: https://shorin.me/blog/2024/06/watermark/index.md It has been a while since I wrote about the challenges researchers face when scanning ancient manuscripts. My last post was about iron gall [ink](https://shorin.me/en/blog/2024/06/chernila/index.md). This post is about watermarks. Watermarks are translucent impressions on paper, created by wires attached to a papermaking mould. The earliest known watermarks appeared in Italy in the late 13th century, and their original purpose was to show that the paper had been made locally rather than imported. Watermarks are used to identify the papermaker and sometimes the place and time of production. Entire catalogues exist to help librarians estimate the age of a manuscript quite accurately from the appearance of its watermark. Watermarks were made in a wide variety of shapes and styles, from geometric patterns to images of animals, flowers and national symbols, as well as words or names. The watermark’s wire outline was sewn onto the horizontal laid wires and vertical chain wires of the papermaking mould using fine wire. As a result, “sewing dots” were impressed into the paper along with the watermark. Beta radiography is currently considered the best method for detecting watermarks – it produces an X-ray image of the paper. A sheet of paper is placed between a radioactive source, usually a plastic sheet impregnated with carbon-14, and X-ray film. X-rays pass more easily through the thinner areas of the paper – the watermark, laid lines and chain lines – so the paper is recorded as black and the watermark as white. The resulting image is highly detailed and shows the watermark clearly, while leaving out any text and/or illustrations that might obscure it. The radioactive source is believed to have no effect on the paper. ## Media ## Original posts - LinkedIn: