Date: 7 Elul 5595
From: Rabbi Moshe Sofer, Rakendorf
To: Rabbi Yosef Yoel Deutsch
The responsum discusses the ritual impurity (tumah) of ink stains on paper, arguing for leniency based on the paper's transformation from its original fibers and its use for purposes other than clothing.
Source: Shu"t Chasam Sofer Collected §81