The only thing that he can exercise control over at that point is when to reenter the scene and extinguish the fire. Take a look at Cai Guo-Qiang's canisters of gunpowder. He has some dozen kinds of eye-dazzling gunpowder-from the black of traditional gunpowder, to smokeless brown gunpowder, to realgar yellow gunpowder. The colors black, brown and yellow are in fact the primary colors of gunpowder drawings.
看蔡國強的「火藥盤」，十多盤琳瑯滿目，從黑色的傳統火藥、無煙的褐色火藥，到摻了雄黃的黃色火藥，黑、褐、黃，構成了「火墨畫」的三原色。