Actually I find they often appear brownish at night, though the crest is often very obvious earlier in the season. I wonder if its the way the daylight reflects off them that makes them appear darkest inky black...
If you can imaging a pom pom made of plastic strip about 1.5cm wide thrown into the pond and anchored using string to the side that's what they have used.
female newts lay their eggs on plants normally and fold over the leaf around the egg, where there aren't plants the females can be reluctant to lay - they happily and readily adopt the plastic strips though.