Rolleiflex orange filter, variable optical density?

[hiroh]

I purchased three color filters for my Rolleiflex 2.8F, and I'd like to check something before I go out to test it.

So, Green and Yellow filters has -1.5 optical density, but Orange says -1.5 -3. What does this mean? Why it has the range of 1.5-3? Is it variable? How do I meter for the orange filter?

 

[BrianShaw]

Rollei Orange filter compensation

The exposure compensation required for this filter is from -1.5 to -3.0 stops and may I know why is this range? Does it has anything to do with the light from the Sun at the raise, noon and at the set?

www.photrio.com

 

[hiroh]

Thanks!