jQuery Chart - CandleStickSeries.reduction
Each point in a financial series has four values or "prices": high, low, open and close. To mirror the changes on the market more clearly, the UI component compares the price of every point with the price of the previous point. Those points whose price has decreased are painted in a specific color. To specify whether high, low, open or close prices of points should be compared, use the level property.
Specifies a color for the points whose price has decreased in comparison to the price of the previous point.