diff -up mutter-3.12.2/src/compositor/meta-background.c.colorchange mutter-3.12.2/src/compositor/meta-background.c
--- mutter-3.12.2/src/compositor/meta-background.c.colorchange	2014-08-09 13:49:27.603141789 +0200
+++ mutter-3.12.2/src/compositor/meta-background.c	2014-08-09 13:55:46.205277383 +0200
@@ -45,12 +45,15 @@
 "uniform float brightness;\n"                                                  \
 "uniform float vignette_sharpness;\n"                                          \
 
+/* 1.0, 1.0, 0.0 is yellow */
+
 #define VIGNETTE_CODE                                                          \
 "vec2 position = cogl_tex_coord_in[0].xy * texture_scale - offset;\n"          \
 "float t = length(2.0 * (position / actor_size));\n"                           \
 "t = clamp(t, 0.0, 1.0);\n"                                                    \
 "float pixel_brightness = mix(1.0, 1.0 - vignette_sharpness, t);\n"            \
-"cogl_color_out.rgb = cogl_color_out.rgb * pixel_brightness * brightness;\n"
+"vec3 constant_color = vec3(1.0, 1.0, 0.0);\n"                                 \
+"cogl_color_out.rgb = mix(cogl_color_out.rgb, constant_color, pixel_brightness * brightness);\n"
 
 /* We allow creating multiple MetaBackgrounds for the same monitor to
  * allow different rendering options to be set for different copies.