-const Material mtl_sph = Material(GREY(0.1), GREY(1.0), 80.0, 0.8, 0.0, 0.0);
-const Material mtl_glass = Material(GREY(0.0), GREY(0.99), 80.0, 0.99, 0.99, 1.52);
-const Material mtl_air = Material(GREY(0.0), GREY(0.99), 80.0, 0.99, 0.99, 1.0);
+const Material mtl_sph = Material(GREY(0.05), GREY(0.8), 80.0, 0.8, 0.0, 0.0);
+const Material mtl_glass = Material(GREY(0.0), GREY(0.8), 80.0, 0.99, 0.99, 1.52);
+const Material mtl_air = Material(GREY(0.0), GREY(0.8), 80.0, 0.99, 0.99, 1.0);