diff --git a/ChangeLog b/ChangeLog
index b8bcec45..d48bf2f0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
 31/8/12 started 7.31.0
 - redone im_Lab2XYZ(), im_XYZ2Lab(), im_Lab2LCh(), im_LCh2Lab(), im_UCS2LCh, 
-  im_LCh2UCS() as classes
+  im_LCh2UCS(), im_XYZ2Yxy(), im_Yxy2XYZ() as classes
 
 13/9/12 started 7.30.3
 - linecache sized itself too large
diff --git a/libvips/colour/Makefile.am b/libvips/colour/Makefile.am
index e8e1be92..c4c498ca 100644
--- a/libvips/colour/Makefile.am
+++ b/libvips/colour/Makefile.am
@@ -12,6 +12,8 @@ libcolour_la_SOURCES = \
 	LCh2UCS.c \
 	UCS2LCh.c \
 	XYZ2Lab.c \
+	XYZ2Yxy.c \
+	Yxy2XYZ.c \
 	im_icc_transform.c \
 	im_Lab2LabQ.c \
 	im_Lab2LabS.c \
@@ -21,9 +23,7 @@ libcolour_la_SOURCES = \
 	im_LabS2LabQ.c \
 	im_LabS2Lab.c \
 	im_lab_morph.c \
-	im_XYZ2Yxy.c \
 	im_float2rad.c \
-	im_Yxy2XYZ.c \
 	im_XYZ2disp.c \
 	im_dE00_fromLab.c \
 	im_dECMC_fromLab.c \
diff --git a/libvips/colour/im_XYZ2Yxy.c b/libvips/colour/XYZ2Yxy.c
similarity index 57%
rename from libvips/colour/im_XYZ2Yxy.c
rename to libvips/colour/XYZ2Yxy.c
index 05a3c2be..dbc3a9e8 100644
--- a/libvips/colour/im_XYZ2Yxy.c
+++ b/libvips/colour/XYZ2Yxy.c
@@ -43,16 +43,23 @@
 #include <math.h>
 
 #include <vips/vips.h>
-#include <vips/internal.h>
 
-/* Process a buffer of data.
- */
-void
-imb_XYZ2Yxy( float *p, float *q, int n )
+#include "colour.h"
+
+typedef VipsColorimetric VipsXYZ2Yxy;
+typedef VipsColorimetricClass VipsXYZ2YxyClass;
+
+G_DEFINE_TYPE( VipsXYZ2Yxy, vips_XYZ2Yxy, VIPS_TYPE_COLORIMETRIC );
+
+static void
+vips_XYZ2Yxy_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 {
+	float *p = (float *) in[0];
+	float *q = (float *) out;
+
 	int i;
 
-	for( i = 0; i < n; i++ ) {
+	for( i = 0; i < width; i++ ) {
 		float X = p[0];
 		float Y = p[1];
 		float Z = p[2];
@@ -72,19 +79,42 @@ imb_XYZ2Yxy( float *p, float *q, int n )
 	}
 }
 
+static void
+vips_XYZ2Yxy_class_init( VipsXYZ2YxyClass *class )
+{
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	object_class->nickname = "XYZ2Yxy";
+	object_class->description = _( "transform XYZ to Yxy" );
+
+	colour_class->process_line = vips_XYZ2Yxy_line;
+	colour_class->interpretation = VIPS_INTERPRETATION_YXY;
+}
+
+static void
+vips_XYZ2Yxy_init( VipsXYZ2Yxy *XYZ2Yxy )
+{
+}
+
 /**
- * im_XYZ2Yxy:
+ * vips_XYZ2Yxy:
  * @in: input image
  * @out: output image
  *
  * Turn XYZ to Yxy.
  *
- * Returns: 0 on success, -1 on error.
+ * Returns: 0 on success, -1 on error
  */
-int 
-im_XYZ2Yxy( IMAGE *in, IMAGE *out )
-{	
-	return( im__colour_unary( "im_XYZ2Yxy", in, out, IM_TYPE_YXY,
-		(im_wrapone_fn) imb_XYZ2Yxy, NULL, NULL ) );
-}
+int
+vips_XYZ2Yxy( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
 
+	va_start( ap, out );
+	result = vips_call_split( "XYZ2Yxy", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}
diff --git a/libvips/colour/im_Yxy2XYZ.c b/libvips/colour/Yxy2XYZ.c
similarity index 57%
rename from libvips/colour/im_Yxy2XYZ.c
rename to libvips/colour/Yxy2XYZ.c
index 7a55deb1..9e7b2c5e 100644
--- a/libvips/colour/im_Yxy2XYZ.c
+++ b/libvips/colour/Yxy2XYZ.c
@@ -43,16 +43,23 @@
 #include <math.h>
 
 #include <vips/vips.h>
-#include <vips/internal.h>
 
-/* Process a buffer of data.
- */
+#include "colour.h"
+
+typedef VipsColorimetric VipsYxy2XYZ;
+typedef VipsColorimetricClass VipsYxy2XYZClass;
+
+G_DEFINE_TYPE( VipsYxy2XYZ, vips_Yxy2XYZ, VIPS_TYPE_COLORIMETRIC );
+
 void
-imb_Yxy2XYZ( float *p, float *q, int n )
+vips_Yxy2XYZ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 {
+	float *p = (float *) in[0];
+	float *q = (float *) out;
+
 	int i;
 
-	for( i = 0; i < n; i++ ) {
+	for( i = 0; i < width; i++ ) {
 		float Y = p[0];
 		float x = p[1];
 		float y = p[2];
@@ -73,19 +80,43 @@ imb_Yxy2XYZ( float *p, float *q, int n )
 	}
 }
 
+static void
+vips_Yxy2XYZ_class_init( VipsYxy2XYZClass *class )
+{
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
+
+	object_class->nickname = "Yxy2XYZ";
+	object_class->description = _( "transform Yxy to XYZ" );
+
+	colour_class->process_line = vips_Yxy2XYZ_line;
+	colour_class->interpretation = VIPS_INTERPRETATION_XYZ;
+}
+
+static void
+vips_Yxy2XYZ_init( VipsYxy2XYZ *Yxy2XYZ )
+{
+}
+
 /**
- * im_Yxy2XYZ:
+ * vips_Yxy2XYZ:
  * @in: input image
  * @out: output image
  *
- * Turn Yxy to XYZ.
+ * Turn XYZ to Yxy.
  *
- * Returns: 0 on success, -1 on error.
+ * Returns: 0 on success, -1 on error
  */
-int 
-im_Yxy2XYZ( IMAGE *in, IMAGE *out )
+int
+vips_Yxy2XYZ( VipsImage *in, VipsImage **out, ... )
 {
-	return( im__colour_unary( "im_Yxy2XYZ", in, out, IM_TYPE_XYZ,
-		(im_wrapone_fn) imb_Yxy2XYZ, NULL, NULL ) );
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "Yxy2XYZ", ap, in, out );
+	va_end( ap );
+
+	return( result );
 }
 
diff --git a/libvips/colour/colour.c b/libvips/colour/colour.c
index 4bc1f11d..98fdd563 100644
--- a/libvips/colour/colour.c
+++ b/libvips/colour/colour.c
@@ -244,14 +244,20 @@ void
 vips_colour_operation_init( void )
 {
 	extern GType vips_Lab2XYZ_get_type( void ); 
+	extern GType vips_XYZ2Lab_get_type( void ); 
 	extern GType vips_Lab2LCh_get_type( void ); 
 	extern GType vips_LCh2Lab_get_type( void ); 
 	extern GType vips_LCh2UCS_get_type( void ); 
 	extern GType vips_UCS2LCh_get_type( void ); 
+	extern GType vips_Yxy2XYZ_get_type( void ); 
+	extern GType vips_XYZ2Yxy_get_type( void ); 
 
 	vips_Lab2XYZ_get_type();
+	vips_XYZ2Lab_get_type();
 	vips_Lab2LCh_get_type();
 	vips_LCh2Lab_get_type();
 	vips_LCh2UCS_get_type();
 	vips_UCS2LCh_get_type();
+	vips_XYZ2Yxy_get_type();
+	vips_Yxy2XYZ_get_type();
 }
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index ee285b15..f7a47725 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -2291,3 +2291,35 @@ im_UCS2LCh( IMAGE *in, IMAGE *out )
 
 	return( 0 );
 }
+
+int 
+im_XYZ2Yxy( IMAGE *in, IMAGE *out )
+{
+	VipsImage *x;
+
+	if( vips_XYZ2Yxy( in, &x, NULL ) )
+		return( -1 );
+	if( im_copy( x, out ) ) {
+		g_object_unref( x );
+		return( -1 );
+	}
+	g_object_unref( x );
+
+	return( 0 );
+}
+
+int 
+im_Yxy2XYZ( IMAGE *in, IMAGE *out )
+{
+	VipsImage *x;
+
+	if( vips_Yxy2XYZ( in, &x, NULL ) )
+		return( -1 );
+	if( im_copy( x, out ) ) {
+		g_object_unref( x );
+		return( -1 );
+	}
+	g_object_unref( x );
+
+	return( 0 );
+}
diff --git a/libvips/include/vips/colour.h b/libvips/include/vips/colour.h
index 63276cb2..cdea862a 100644
--- a/libvips/include/vips/colour.h
+++ b/libvips/include/vips/colour.h
@@ -126,6 +126,10 @@ int vips_LCh2UCS( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_UCS2LCh( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
+int vips_XYZ2Yxy( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
+int vips_Yxy2XYZ( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
 
 void vips_col_Lab2XYZ( float L, float a, float b, 
 	float *X, float *Y, float *Z );
@@ -174,8 +178,6 @@ int im_Lab2UCS( VipsImage *in, VipsImage *out );
 int im_XYZ2UCS( VipsImage *in, VipsImage *out );
 int im_sRGB2XYZ( VipsImage *in, VipsImage *out );
 int im_XYZ2sRGB( VipsImage *in, VipsImage *out );
-int im_Yxy2XYZ( VipsImage *in, VipsImage *out );
-int im_XYZ2Yxy( VipsImage *in, VipsImage *out );
 
 int im_dECMC_fromLab( VipsImage *in1, VipsImage *in2, VipsImage *out );
 int im_dE00_fromLab( VipsImage *in1, VipsImage *in2, VipsImage *out );
diff --git a/libvips/include/vips/vips7compat.h b/libvips/include/vips/vips7compat.h
index d37f8860..75755439 100644
--- a/libvips/include/vips/vips7compat.h
+++ b/libvips/include/vips/vips7compat.h
@@ -716,6 +716,8 @@ int im_Lab2LCh( VipsImage *in, VipsImage *out );
 int im_LCh2Lab( VipsImage *in, VipsImage *out );
 int im_LCh2UCS( VipsImage *in, VipsImage *out );
 int im_UCS2LCh( VipsImage *in, VipsImage *out );
+int im_XYZ2Yxy( VipsImage *in, VipsImage *out );
+int im_Yxy2XYZ( VipsImage *in, VipsImage *out );
 
 /* ruby-vips uses this
  */