The lenses in your sunglasses are polarized I am guessing. The ND issue, I would try taking the image with no change in exposure while your at it.
On Sat, Jul 23, 2016, 04:40 Sebastian <[email protected]> wrote: > It could be worth trying to copy the colors of picture without filter to > a picture taken with ND-filter using the Color mapping: > http://www.darktable.org/2013/04/color-mapping/ > > > On 07/12/2016 06:27 PM, Stefan Klinger wrote: > > Hi, I have two questions regarding optical Filters: > > > > (1) My ND-Filter creates a slight color cast, which I would like to > > undo semi-automatically: The recipe I have in mind would be to take > > two pictures of a white surface, once with and once without the > > optical filter in place. Using the same light source and camera WB, > > but different exposure to compensate for brightness, the difference > > between the two pictures should express the unwanted color cast. Can > > DT use this to calculate an inverse filter? > > > > (2) Similar Problem, in the other direction: Sometimes I see landscape > > through sunglasses, and it looks nicer than without. Can I dell DT to > > replicate the effect of my sunglasses? The recipe would be similar as > > above: Take two shots of a defined white surface, once directly, once > > through the glasses. The difference between the two pictures should > > be used to derive a filter function that adds the “sunglasses effect” > > in post processing. > > > > Thank you > > Stefan > > > > > > -- > python programming - mail server - photo - video - https://sebix.at > cryptographic key at https://sebix.at/DC9B463B.asc and on public > keyservers > > > ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected]
