Does the color of a hammer candle matter?

The color of a hammer candle does not significantly matter. What drives the signal is the structure: a small body near the top, a long lower shadow roughly twice the body length, and a location at the end of a downtrend near support. A green hammer is marginally more bullish than a red one because buyers fully reclaimed the session, but a red hammer stays valid when shape and context confirm rejection of lower prices.