As part of package with my Rolleiflex, I have received original sun protection "tulip" and two color filters for b/w photography, all in nice also original leather cases. For a long time I haven't used them, but recently I gave a try to the red filter - I wanted to achieve effect of nice dramatic sky, not over exposed, but also correctly exposed rest of the frame.
I studied a bit in internet about exposure compensation while using red filter and found out taht in most cases it is needed to increase exposure about 3 stops. Then I also checked with my light meter, where I got results closer to +2 stops depending on the frame. The filter itself mentioned the range from 1.5stops to 3stops (not much helpful :-/). Anyway first attempt was from my balcony and second from pedestrian part of Ag Nikolaou overlooking the sea, using +2 stops in both shots.
As You can easily notice, I have failed :-( Consider also the fact that I have darkened a bit the sky after scanning! Not sure why I failed... as I used the lesser compensation in fact. Imagine how over blown they would be with +3stops! I think I will go for minor +1 next time...
Photos: Rolleiflex Automat w/Tessar 75mm f/3.5, Rollei red filter, Kodak Tmax 400