Measured under TAPPI T 480 or ISO 8254-1, it lights the sample at a grazing 75 degrees, where even modest smoothness gives a readable signal. Matte grades often read below 25, silk and satin roughly 30 to 55, and gloss grades about 65 and up. Readings are taken in both machine and cross directions, because calendering and coating streaks can make gloss direction-dependent.
75-degree gloss is 68 on the felt side and 63 on the wire side, so the two-sidedness is back.
Also heard as
- TAPPI gloss
- 75 gloss
Do not mix it up with
- 20-degree gloss: 20 degrees is reserved for very glossy surfaces whose 75-degree readings bunch up near the top of the scale.
Related terms
Gloss
The mirror-like shine of a paper or print surface, measured as specular reflectance at a defined angle.
20-degree gloss
Specular gloss measured at a steep 20 degrees, used to separate very glossy papers, boards and prints.
Two-sidedness
Difference in properties between the two faces of a paper sheet, such as color, brightness, gloss or texture.
Supercalender
Off-machine stack of alternating steel and resilient filled rolls that gives paper high gloss and smoothness.