On the fast day of Tisha b’Av, which began last night and ends this evening, many synagogues have the custom of dimming the lights for the evening reading of the book of Lamentations; others adhere to an older custom of lighting candles. Menachem Wecker notes how this practice has left stains on historic books:
Chaim Louis Meiselman, [a Judaica librarian at the University of Pennsylvania, described] a holiday prayer book, a maḥzor, in the unique Roman rite that dates to 1718 or 1719 from the northern Italian city of Mantua. On the opening page of Lamentations in the book, which is part of the collection of University of Pennsylvania, one can see a stain from wax that dripped on the page from a candle, which a reader must have used to follow along with the text.
Reading by candlelight was associated with reading Lamentations on Tisha B’Av, Meiselman told JNS. “The synagogue lights are darkened at that point in the liturgy, and the reader or user then takes a candle and sits close to the book,” he said. “The room is otherwise dark.” Meiselman cited an illustration from a German book, belonging to a mohel, which dates to 1740 and is part of the Jewish Theological Seminary collection. In the drawing, three men sit on a synagogue floor. The candles have been removed from the chandelier above, and one of the men holds a candle.
The Penn librarian also has a maḥzor, which dates to 1734 and comes from Sulzbach am Main, Germany, in his personal collection. The book has many wax drippings on the page for Lamentations.
Read more on JNS: https://www.jns.org/jewish-and-israeli-holidays/tisha-bav/23/7/25/305599/