The heading draws a key line at 10% mechanical fiber content. Paper and paperboard for writing or printing with not more than 10% mechanical fiber falls under subheadings 481013–481019, while grades exceeding that threshold — including light-weight coated (LWC) paper — fall under 481022 or 481029. Accurate fiber analysis documentation is essential for correct classification.

The kraft subheadings cover paper and paperboard composed of more than 95% chemical wood fiber and are oriented toward packaging rather than graphic end-uses. Within the bleached kraft group, the split is by basis weight — not over 150 g/m² (481031) versus over 150 g/m² (481032) — while 481039 covers unbleached kraft grades not intended for graphic purposes.