Gloss
Also: gloss, paper gloss, TAPPI gloss
The fraction of incident light a paper reflects at a fixed angle, measured at 20°, 60°, or 75° in a gloss meter.
Gloss measures how glossy (mirror-like) a paper surface is. A glossmeter shines light at a fixed angle and measures the fraction reflected at the same angle. Higher values mean glossier paper. TAPPI T480 and ISO 8254 define the test at 75°, the most common angle for paper.
Matte coated papers typically run 15 to 30 gloss units. Silk coated runs 40 to 60. High-gloss coated hits 70 to 85. Gloss correlates with perceived print sharpness but can hurt readability for long-form text.
Related
- Smoothness. The surface regularity of a paper, measured by air leak under a pressurized head (Parker Print Surf, Bendtsen).