What color is red cabbage juice with epsom salts and ammonia?

Red cabbage juice is a natural pH indicator that changes color based on acidity or alkalinity. When mixed with Epsom salts (magnesium sulfate), the juice may remain a purplish hue, but when ammonia (which is alkaline) is added, the color shifts to a greenish-yellow. This color change occurs because the ammonia raises the pH, causing the anthocyanins in the cabbage to alter their structure and absorb light differently.