That white line is a rainbow 🙂 It’s the first time I saw a rainbow at sea, so I took tons of photos 😀 I’ll upload them soon! 😀 I used an Infrared filter to make the water as still as possible!
Location: São Vicente – Madeira island -> Portugal
Shutter speed: 60 seconds
Focal Length: 18mm
Filters: Hoya [Infrared] R72