diff --git a/cogl-material.h b/cogl-material.h
index 510ce8238..44a837564 100644
--- a/cogl-material.h
+++ b/cogl-material.h
@@ -138,6 +138,11 @@ gboolean cogl_is_material (CoglHandle handle);
  *
  * This is the basic color of the material, used when no lighting is enabled.
  *
+ * Note that if you don't add any layers to the material then the color
+ * will be blended unmodified with the destination; the default blend
+ * expects premultiplied colors: for example, use (0.5, 0.0, 0.0, 0.5) for
+ * semi-transparent red. See cogl_color_premultiply().
+ *
  * The default value is (1.0, 1.0, 1.0, 1.0)
  *
  * Since 1.0
@@ -475,6 +480,11 @@ void cogl_material_set_alpha_test_function (CoglHandle            material,
  * </programlisting>
  * </section>
  *
+ * The default blend string is:
+ *  "RGBA = ADD (SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
+ * That gives normal alpha-blending when the calculated color for the material
+ * is in premultiplied form.
+ *
  * Returns: TRUE if the blend string was successfully parsed, and the described
  *          blending is supported by the underlying driver/hardware. If there
  *          was an error, it returns FALSE.
diff --git a/cogl.h.in b/cogl.h.in
index a468cf717..64d57fc4f 100644
--- a/cogl.h.in
+++ b/cogl.h.in
@@ -455,8 +455,13 @@ void            cogl_set_source               (CoglHandle material);
  * cogl_set_source_color:
  * @color: a #CoglColor
  *
- * Sets the source color using normalized values for each component.
- * This color will be used for any subsequent drawing operation.
+ * This is a convenience function for creating a solid fill source material
+ * from the given color. This color will be used for any subsequent drawing
+ * operation.
+ *
+ * The color will be premultiplied by Cogl, so the color should be
+ * non-premultiplied. For example: use (1.0, 0.0, 0.0, 0.5) for
+ * semi-transparent red.
  *
  * See also cogl_set_source_color4ub() and cogl_set_source_color4f()
  * if you already have the color components.
diff --git a/common/cogl-material.c b/common/cogl-material.c
index 831fa30f1..7e3935bff 100644
--- a/common/cogl-material.c
+++ b/common/cogl-material.c
@@ -109,7 +109,7 @@ cogl_material_new (void)
   material->blend_constant[2] = 0;
   material->blend_constant[3] = 0;
 #endif
-  material->blend_src_factor_rgb = GL_SRC_ALPHA;
+  material->blend_src_factor_rgb = GL_ONE;
   material->blend_dst_factor_rgb = GL_ONE_MINUS_SRC_ALPHA;
   material->flags |= COGL_MATERIAL_FLAG_DEFAULT_BLEND_FUNC;
 
diff --git a/common/cogl.c b/common/cogl.c
index 336303917..5857db2d3 100644
--- a/common/cogl.c
+++ b/common/cogl.c
@@ -250,12 +250,17 @@ cogl_get_backface_culling_enabled (void)
 void
 cogl_set_source_color (const CoglColor *color)
 {
+  CoglColor premultiplied;
+
   _COGL_GET_CONTEXT (ctx, NO_RETVAL);
 
   /* In case cogl_set_source_texture was previously used... */
   cogl_material_remove_layer (ctx->default_material, 0);
 
-  cogl_material_set_color (ctx->default_material, color);
+  premultiplied = *color;
+  cogl_color_premultiply (&premultiplied);
+  cogl_material_set_color (ctx->default_material, &premultiplied);
+
   cogl_set_source (ctx->default_material);
 }
 
diff --git a/gl/cogl-texture.c b/gl/cogl-texture.c
index 3af78f9a0..2ee50617c 100644
--- a/gl/cogl-texture.c
+++ b/gl/cogl-texture.c
@@ -1085,18 +1085,20 @@ _cogl_pixel_format_to_gl (CoglPixelFormat  format,
   GLenum          glformat = 0;
   GLenum          gltype = 0;
 
-  /* No premultiplied formats accepted  by GL
-   * (FIXME: latest hardware?) */
-
-  if (format & COGL_PREMULT_BIT)
-    format = (format & COGL_UNPREMULT_MASK);
-
-  /* Everything else accepted
-   * (FIXME: check YUV support) */
-  required_format = format;
+  /* If PREMULT_BIT isn't specified, that means that we premultiply
+   * textures with alpha before uploading to GL; once we are in GL land,
+   * everything is premultiplied.
+   *
+   * Everything else accepted (FIXME: check YUV support)
+   */
+  if ((format & COGL_A_BIT) != 0 &&
+      format != COGL_PIXEL_FORMAT_A_8)
+    required_format = format | COGL_PREMULT_BIT;
+  else
+    required_format = format;
 
   /* Find GL equivalents */
-  switch (format)
+  switch (format & COGL_UNPREMULT_MASK)
     {
     case COGL_PIXEL_FORMAT_A_8:
       glintformat = GL_ALPHA;
diff --git a/gles/cogl-texture.c b/gles/cogl-texture.c
index ae3e437b8..f9b6e0b78 100644
--- a/gles/cogl-texture.c
+++ b/gles/cogl-texture.c
@@ -1184,18 +1184,20 @@ _cogl_pixel_format_to_gl (CoglPixelFormat  format,
   GLenum          glformat = 0;
   GLenum          gltype = 0;
 
-  /* No premultiplied formats accepted  by GL
-   * (FIXME: latest hardware?) */
-
-  if (format & COGL_PREMULT_BIT)
-    format = (format & COGL_UNPREMULT_MASK);
-
-  /* Everything else accepted
-   * (FIXME: check YUV support) */
-  required_format = format;
+  /* If PREMULT_BIT isn't specified, that means that we premultiply
+   * textures with alpha before uploading to GL; once we are in GL land,
+   * everything is premultiplied.
+   *
+   * Everything else accepted (FIXME: check YUV support)
+   */
+  if ((format & COGL_A_BIT) != 0 &&
+      format != COGL_PIXEL_FORMAT_A_8)
+    required_format = format | COGL_PREMULT_BIT;
+  else
+    required_format = format;
 
   /* Find GL equivalents */
-  switch (format)
+  switch (format & COGL_UNPREMULT_MASK)
     {
     case COGL_PIXEL_FORMAT_A_8:
       glintformat = GL_ALPHA;
@@ -1226,6 +1228,7 @@ _cogl_pixel_format_to_gl (CoglPixelFormat  format,
       glformat = GL_RGBA;
       gltype = GL_UNSIGNED_BYTE;
       required_format = COGL_PIXEL_FORMAT_RGBA_8888;
+      required_format |= (format & COGL_PREMULT_BIT);
       break;
 
       /* The following three types of channel ordering