diff --git a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
index 21a462e2db71a00203f46150dbd925056fa26b05..5999063ae53007f519f81dea89eb1a5f5b08578d 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
@@ -254,7 +254,7 @@ void main()
     vec4 final_color = vec4(diffuse_linear.rgb, 0.0);
 
 #if (DIFFUSE_ALPHA_MODE == DIFFUSE_ALPHA_MODE_EMISSIVE)
-    final_color.a = diffuse_linear.a;
+    final_color.a = diffuse_linear.a * 0.5; // SL-12171
 #endif
 
     final_color.a = max(final_color.a, emissive_brightness);