I've seen bits and pieces of this information posted around, but never the whole thing at once and nobody really answered when I used to ask. So here's a simple chart that's useful for neutral Grey's and general brightness comparison.
These numbers assume a flat/matte (lambertian) screen/surface.
N10----1.0gain
N9.5----0.9gain
N9-----0.79gain
N8.5----0.68gain
N8-----0.59gain
N7.5----0.5gain
N7-----0.43gain
N6.5----0.37gain
N6-----0.3gain
N5.5----0.24gain
N5-----0.2gain
N4.5----0.16gain
N4-----0.12gain
N3.5----0.09gain
N3-----0.07gain
N2.5----0.05gain
N2-----0.03gain
N1.5----0.02gain
N1-----0.01gain
For reference, duct-tape is about N6.
Many white-looking surfaces range from N8.5-N9.5.
Generally N3.5 and below looks black.
Gain and reflectance is easy..1.0gain is 100% as reflective as a perfectly white flat/matte, 0.5gain is 50%, 0.2gain is 20% and so on.
These numbers assume a flat/matte (lambertian) screen/surface.
N10----1.0gain
N9.5----0.9gain
N9-----0.79gain
N8.5----0.68gain
N8-----0.59gain
N7.5----0.5gain
N7-----0.43gain
N6.5----0.37gain
N6-----0.3gain
N5.5----0.24gain
N5-----0.2gain
N4.5----0.16gain
N4-----0.12gain
N3.5----0.09gain
N3-----0.07gain
N2.5----0.05gain
N2-----0.03gain
N1.5----0.02gain
N1-----0.01gain
For reference, duct-tape is about N6.
Many white-looking surfaces range from N8.5-N9.5.
Generally N3.5 and below looks black.
Gain and reflectance is easy..1.0gain is 100% as reflective as a perfectly white flat/matte, 0.5gain is 50%, 0.2gain is 20% and so on.