diff --git a/src/lib.rs b/src/lib.rs
index 9ae7d9d..515fb6a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -264,7 +264,8 @@ impl Core {
 				value += w;
 			}
 			value *= weight;
-			let r = 0.01;
+			value = 3. * (1. - (1. + value).recip());
+			let r = args.accum_sigma;
 			let color = vec3(value, value - 1., value - 2.).clamp(Vec3::splat(0.), Vec3::splat(1.));
 			let vertex = |off: Vec3| Vertex {
 				pos: hit.base + r * off,