Developed by Dr Alexander Elder, the Elder-ray indicator measures buying and selling pressure in the market. The Elder-ray is often used as part of the Triple Screen trading system but may also be used on its own. Dr Elder uses a 13-day exponential moving average (EMA) to indicate the market consensus of value. Bull Power measures the ability of buyers to drive prices above the consensus of value. Bear Power reflects the ability of sellers to drive prices below the average consensus of value. Bull Power is calculated by subtracting the 13-day EMA from the day's High. Bear power subtracts the 13-day EMA from the day's Low. WARNING: - For purpose educate only - This script to change bars colors.