Usually, the candlestick takes its colour from its close against the previous close. So if the close of the last candle is higher than the close of the previous one it will be green (on some charts blue): if it is lower it will be red.
Some charts can be re-set so that you have solid coloured bodies or hollow bodies depending on whether the candle’s own close was higher or lower than its own open.
If you have a chart system that can be re-set to show different colour by comparing the last candle’s high and low with the previous candle’s high and low, the candles are usually just displayed as bars not candles, and the usual colour scheme is -
higher high and higher low - blue
lower high and lower low - red
lower high but higher low - orange (an “inside bar”)
higher high but lower low - black (an “outside bar”)
high and low same as previous high and low - green