Some papers include a 2–3% calcium carbonate buffer to protect against environmental acids.
There is also a specific luxury brand called Proper Papers , though they primarily specialize in premium rolling papers rather than traditional stationery or art paper. Key Characteristics of "Proper" Archival Paper Acideria Talla
To be considered "proper" for archival or professional art use, paper should meet these standards: Some papers include a 2–3% calcium carbonate buffer