What does a black candlestick mean?

Hi Marko, thanks for asking!

When stocks are closed, information is derived from this close, and according to the color of this candlestick, we can conclude if the stock has closed on a lower or higher value than the prior close.

When a candlestick is filled with black color that means that the close was higher than the previous close, which is a positive sign and indicates an uptrend.