thank, yes I use this B+W 110 and 106. They have a pretty strong red color cast, but since I want to convert this to black and white anyway, it doesn't matter. For my landscape work, which is sometimes color long exposure, I use a Hoya ND400 and Hoya ND8. These filters also have a color cast, but it's so much less than the B+Ws. So a correction in postprocessing is quite easy.