Glossary
GSM
Grams per square meter — paper weight, not quality.
GSM measures paper density: 52 gsm Tomoe River is onion-skin thin, 80 gsm is standard notebook, 90 gsm Rhodia is the fountain-pen default, 160 gsm approaches card stock.
Weight predicts opacity and hand-feel, not fountain-pen behavior — coating and sizing do that. The thinnest famous fountain-pen paper outperforms copy paper three times its weight.
Related terms
