Spoken as d-zero, it lights the sample from all directions with an integrating sphere and collects reflected light along the surface normal. ISO brightness, printing opacity and CIE whiteness all use it, because the readings depend little on surface texture or grain direction. Since no light reaches the sample from the viewing direction, the mirror-like gloss component is left out, so coated and uncoated sheets can be compared fairly.
Their lab is d/8 with specular included and ours is d/0, so don't expect our L-star numbers to match theirs.
Also heard as
- d/0
- diffuse/normal geometry
Do not mix it up with
- 45/0 geometry: 45/0 lights the sample from a fixed angle, so it responds more to texture, felt marks and grain.
Related terms
Integrating sphere
Hollow sphere lined with a highly reflective matte white that bathes a sample in diffuse light from all directions.
45/0 geometry
Measurement setup with the sample lit at 45 degrees and viewed straight on, or the reverse.
ISO brightness
Diffuse blue reflectance factor at 457 nm, measured with d/0 geometry and UV content matched to illuminant C.
Gloss trap
Black absorbing port in an integrating sphere that removes mirror-like surface reflection from a measurement.