Candlesticks in basic charting tools traditionally use either white or green to show an up day and black or red to show a down day. The color of the candlestick is irrelevant to the analysis, but the color makes it easier to detect where opening and closing prices are relative to each other for that day.
The black filled candlesticks indicated that the closing price is lower than the open price. This is known as a down day or a red day. This makes it easier to see that there may have been a down day even though the trend is still buy.
If the closing price is higher than the open price, then the candle will be filled with the signal color of BUY (green), HOLD (yellow) or SELL (red) as opposed to referencing a stock’s performance for the trading day.
To change the settings from signal view to candlestick view click the dropdown menu.