diff --git a/ChangeLog b/ChangeLog
index c17de3e6..bc236cb7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,10 +10,15 @@
 - rename VIPS_OPERATION_RELATIONAL_NOTEQUAL as VIPS_OPERATION_RELATIONAL_NOTEQ
   for consistency
 - python vips8 binding
-- python vips8 test suite: test_arithmetic.py
+- python vips8 test suite: test_arithmetic.py, test_colour.py,
+  test_conversion.py
 - better extra band handling by colour, again
 - move zoomify ImageProperties file, now a better match to the offical tool
 
+8/9/14 started 7.40.10
+- icc_import and icc_transform checks the input profile for compatibility 
+  with the image, thanks James
+
 8/9/14 started 7.40.9
 - support jfif resunit "none"
 - support GRAY as an input and output ICC space
diff --git a/libvips/colour/icc_transform.c b/libvips/colour/icc_transform.c
index 12ef4243..c11a6a27 100644
--- a/libvips/colour/icc_transform.c
+++ b/libvips/colour/icc_transform.c
@@ -28,6 +28,9 @@
  * 	- support XYZ as an alternative PCS
  * 10/9/14
  * 	- support GRAY as an input and output space
+ * 29/9/14
+ * 	- check input profiles for compatibility with the input image, thanks
+ * 	  James
  */
 
 /*
@@ -456,6 +459,86 @@ vips_check_intent( const char *domain,
 				_( "input" ) : _( "output" ) );
 }
 
+static int
+vips_icc_profile_needs_bands( cmsHPROFILE profile )
+{
+	int needs_bands;
+
+	switch( cmsGetColorSpace( profile ) ) {
+#ifdef HAVE_LCMS2
+	case cmsSigGrayData:
+		needs_bands = 1;
+		break;
+#endif /*HAVE_LCMS2*/
+
+	case cmsSigRgbData:
+	case cmsSigLabData:
+	case cmsSigXYZData:
+		needs_bands = 3;
+		break;
+
+	case cmsSigCmykData:
+		needs_bands = 4;
+		break;
+
+	default:
+		needs_bands = -1;
+		break;
+	}
+
+	return( needs_bands );
+}
+
+static cmsHPROFILE
+vips_icc_load_profile_image( const char *domain, VipsImage *image )
+{
+	void *data;
+	size_t data_length;
+	cmsHPROFILE profile;
+
+	if( !vips_image_get_typeof( image, VIPS_META_ICC_NAME ) )
+		return( NULL ); 
+
+	if( vips_image_get_blob( image, VIPS_META_ICC_NAME, 
+		&data, &data_length ) ||
+		!(profile = cmsOpenProfileFromMem( data, data_length )) ) {
+		vips_warn( domain, "%s", _( "corrupt embedded profile" ) );
+		return( NULL ); 
+	}
+
+	if( image->Bands != vips_icc_profile_needs_bands( profile ) ) {
+		VIPS_FREEF( cmsCloseProfile, profile );
+		vips_warn( domain, 
+			"%s", _( "embedded profile incompatible with image" ) );
+		return( NULL );
+	}
+
+	return( profile );
+}
+
+static cmsHPROFILE
+vips_icc_load_profile_file( const char *domain, 
+	VipsImage *image, const char *filename )
+{
+	cmsHPROFILE profile;
+
+	if( !(profile = cmsOpenProfileFromFile( filename, "r" )) ) {
+		vips_error( domain, 
+			_( "unable to open profile \"%s\"" ), filename );
+		return( NULL );
+	}
+
+	if( image->Bands != vips_icc_profile_needs_bands( profile ) ) {
+		VIPS_FREEF( cmsCloseProfile, profile );
+		vips_warn( domain, 
+			_( "profile \"%s\" incompatible with image" ),
+			filename );
+		return( NULL );
+	}
+
+	return( profile );
+}
+
 static int
 vips_icc_import_build( VipsObject *object )
 {
@@ -477,30 +560,16 @@ vips_icc_import_build( VipsObject *object )
 
 	if( code->in &&
 		(import->embedded ||
-			!import->input_profile_filename) &&
-		vips_image_get_typeof( code->in, VIPS_META_ICC_NAME ) ) {
-		void *data;
-		size_t data_length;
+			!import->input_profile_filename) )
+		icc->in_profile = vips_icc_load_profile_image( class->nickname,
+			code->in );
 
-		if( vips_image_get_blob( code->in, VIPS_META_ICC_NAME, 
-			&data, &data_length ) ||
-			!(icc->in_profile = cmsOpenProfileFromMem( 
-				data, data_length )) ) {
-			vips_error( class->nickname,
-				"%s", _( "unable to load embedded profile" ) );
-			return( -1 );
-		}
-	}
-	else if( import->input_profile_filename ) {
-		if( !(icc->in_profile = cmsOpenProfileFromFile(
-			import->input_profile_filename, "r" )) ) {
-			vips_error( class->nickname,
-				_( "unable to open profile \"%s\"" ), 
-				import->input_profile_filename );
-			return( -1 );
-		}
-	}
-	else {
+	if( !icc->in_profile &&
+		import->input_profile_filename ) 
+		icc->in_profile = vips_icc_load_profile_file( class->nickname,
+			code->in, import->input_profile_filename );
+
+	if( !icc->in_profile ) {
 		vips_error( class->nickname, "%s", _( "no input profile" ) ); 
 		return( -1 );
 	}
@@ -902,30 +971,16 @@ vips_icc_transform_build( VipsObject *object )
 
 	if( code->in &&
 		(transform->embedded ||
-			!transform->input_profile_filename) &&
-		vips_image_get_typeof( code->in, VIPS_META_ICC_NAME ) ) {
-		void *data;
-		size_t data_length;
+			!transform->input_profile_filename) )
+		icc->in_profile = vips_icc_load_profile_image( class->nickname,
+			code->in );
 
-		if( vips_image_get_blob( code->in, VIPS_META_ICC_NAME, 
-			&data, &data_length ) ||
-			!(icc->in_profile = cmsOpenProfileFromMem( 
-				data, data_length )) ) {
-			vips_error( class->nickname,
-				"%s", _( "unable to load embedded profile" ) );
-			return( -1 );
-		}
-	}
-	else if( transform->input_profile_filename ) {
-		if( !(icc->in_profile = cmsOpenProfileFromFile(
-			transform->input_profile_filename, "r" )) ) {
-			vips_error( class->nickname,
-				_( "unable to open profile \"%s\"" ), 
-				transform->input_profile_filename );
-			return( -1 );
-		}
-	}
-	else {
+	if( !icc->in_profile &&
+		transform->input_profile_filename ) 
+		icc->in_profile = vips_icc_load_profile_file( class->nickname,
+			code->in, transform->input_profile_filename );
+
+	if( !icc->in_profile ) {
 		vips_error( class->nickname, "%s", _( "no input profile" ) ); 
 		return( -1 );
 	}
diff --git a/libvips/iofuncs/util.c b/libvips/iofuncs/util.c
index af287175..1942dd1a 100644
--- a/libvips/iofuncs/util.c
+++ b/libvips/iofuncs/util.c
@@ -575,7 +575,8 @@ vips__file_open_read( const char *filename, const char *fallback_dir,
 	if( (fp = fopen( filename, mode )) )
 		return( fp );
 
-	if( fallback_dir && !filename_hasdir( filename ) ) {
+	if( fallback_dir && 
+		!filename_hasdir( filename ) ) {
 		char *path;
 
 		path = g_build_filename( fallback_dir, filename, NULL );
@@ -586,7 +587,7 @@ vips__file_open_read( const char *filename, const char *fallback_dir,
 			return( fp );
 	}
 
-	vips_error( "vips__file_open_read", 
+	vips_error_system( errno, "vips__file_open_read", 
 		_( "unable to open file \"%s\" for reading" ), filename );
 
 	return( NULL );
@@ -608,7 +609,7 @@ vips__file_open_write( const char *filename, gboolean text_mode )
 #endif /*BINARY_OPEN*/
 
         if( !(fp = fopen( filename, mode )) ) {
-		vips_error( "vips__file_open_write", 
+		vips_error_system( errno, "vips__file_open_write", 
 			_( "unable to open file \"%s\" for writing" ), 
 			filename );
 		return( NULL );