diff --git a/wadsrc/static/shaders/glsl/present.fp b/wadsrc/static/shaders/glsl/present.fp
index 4f5c7cffa..31c1217cb 100644
--- a/wadsrc/static/shaders/glsl/present.fp
+++ b/wadsrc/static/shaders/glsl/present.fp
@@ -11,7 +11,7 @@ vec4 ApplyGamma(vec4 c)
 {
 	vec3 val = c.rgb * Contrast - (Contrast - 1.0) * 0.5;
 	val += Brightness * 0.5;
-	val = pow(val, vec3(InvGamma));
+	val = pow(max(val, vec3(0.0)), vec3(InvGamma));
 	return vec4(val, c.a);
 }