Fulling Mill Black Weighted Nymph

Outline beats colour in dirty water

In cold or coloured water a fish sees an outline long before it sees a colour, and black gives the hardest outline there is when it is viewed from below against a bright surface. That is the whole case for a dark nymph early in the season, and it is why black keeps working when carefully matched patterns do not. The weight is built in rather than added at the head, so it sinks evenly and fishes level.