diff --git a/engines/grim/gfx_opengl.cpp b/engines/grim/gfx_opengl.cpp
index d3e8d70bdb1..fab0496a20f 100644
--- a/engines/grim/gfx_opengl.cpp
+++ b/engines/grim/gfx_opengl.cpp
@@ -158,6 +158,8 @@ byte *GfxOpenGL::setupScreen(int screenW, int screenH, bool fullscreen) {
 
 	GLfloat ambientSource[] = { 0.0f, 0.0f, 0.0f, 1.0f };
 	glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientSource);
+	GLfloat diffuseReflectance[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+	glMaterialfv(GL_FRONT, GL_DIFFUSE, diffuseReflectance);
 
 	if (g_grim->getGameType() == GType_GRIM) {
 		glPolygonOffset(-6.0, -6.0);
diff --git a/engines/grim/gfx_tinygl.cpp b/engines/grim/gfx_tinygl.cpp
index 9fc81907f4a..df45510ecd5 100644
--- a/engines/grim/gfx_tinygl.cpp
+++ b/engines/grim/gfx_tinygl.cpp
@@ -103,6 +103,8 @@ byte *GfxTinyGL::setupScreen(int screenW, int screenH, bool fullscreen) {
 
 	TGLfloat ambientSource[] = { 0.0f, 0.0f, 0.0f, 1.0f };
 	tglLightModelfv(TGL_LIGHT_MODEL_AMBIENT, ambientSource);
+	TGLfloat diffuseReflectance[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+	tglMaterialfv(TGL_FRONT, TGL_DIFFUSE, diffuseReflectance);
 
 	// we now generate a buffer (id 1), which we will use as a backing buffer, where the actors' clean buffers
 	// will blit to. everu frame this will be blitted to screen, but the actors' buffers will be blitted to