diff --git a/libvips/colour/LCh2Lab.c b/libvips/colour/LCh2Lab.c
index 5cf39e60..deec3827 100644
--- a/libvips/colour/LCh2Lab.c
+++ b/libvips/colour/LCh2Lab.c
@@ -52,10 +52,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsLCh2Lab;
-typedef VipsColourSpaceClass VipsLCh2LabClass;
+typedef VipsColourTransform VipsLCh2Lab;
+typedef VipsColourTransformClass VipsLCh2LabClass;
 
-G_DEFINE_TYPE( VipsLCh2Lab, vips_LCh2Lab, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsLCh2Lab, vips_LCh2Lab, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /* Process a buffer of data.
  */
diff --git a/libvips/colour/LCh2UCS.c b/libvips/colour/LCh2UCS.c
index d2e01ccc..da09512b 100644
--- a/libvips/colour/LCh2UCS.c
+++ b/libvips/colour/LCh2UCS.c
@@ -48,10 +48,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsLCh2CMC;
-typedef VipsColourSpaceClass VipsLCh2CMCClass;
+typedef VipsColourTransform VipsLCh2CMC;
+typedef VipsColourTransformClass VipsLCh2CMCClass;
 
-G_DEFINE_TYPE( VipsLCh2CMC, vips_LCh2CMC, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsLCh2CMC, vips_LCh2CMC, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /* I ordered this paper from the library and it took ages. For reference, the
  * recommended short formula are:
diff --git a/libvips/colour/Lab2LCh.c b/libvips/colour/Lab2LCh.c
index a33b7bc7..30b58052 100644
--- a/libvips/colour/Lab2LCh.c
+++ b/libvips/colour/Lab2LCh.c
@@ -46,10 +46,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsLab2LCh;
-typedef VipsColourSpaceClass VipsLab2LChClass;
+typedef VipsColourTransform VipsLab2LCh;
+typedef VipsColourTransformClass VipsLab2LChClass;
 
-G_DEFINE_TYPE( VipsLab2LCh, vips_Lab2LCh, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsLab2LCh, vips_Lab2LCh, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /**
  * vips_col_ab2h:
diff --git a/libvips/colour/Lab2XYZ.c b/libvips/colour/Lab2XYZ.c
index 8ae42ec6..7658b79e 100644
--- a/libvips/colour/Lab2XYZ.c
+++ b/libvips/colour/Lab2XYZ.c
@@ -62,7 +62,7 @@
 #include "pcolour.h"
 
 typedef struct _VipsLab2XYZ {
-	VipsColourSpace parent_instance;
+	VipsColourTransform parent_instance;
 
 	/* The colour temperature -- default to D65. 
 	 */
@@ -76,9 +76,9 @@ typedef struct _VipsLab2XYZ {
 
 } VipsLab2XYZ;
 
-typedef VipsColourSpaceClass VipsLab2XYZClass;
+typedef VipsColourTransformClass VipsLab2XYZClass;
 
-G_DEFINE_TYPE( VipsLab2XYZ, vips_Lab2XYZ, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsLab2XYZ, vips_Lab2XYZ, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /* Process a buffer of data.
  */
diff --git a/libvips/colour/UCS2LCh.c b/libvips/colour/UCS2LCh.c
index 280ea395..dfec05ae 100644
--- a/libvips/colour/UCS2LCh.c
+++ b/libvips/colour/UCS2LCh.c
@@ -58,10 +58,10 @@ static float LI[1001];
 static float CI[3001];
 static float hI[101][361];
 
-typedef VipsColourSpace VipsCMC2LCh;
-typedef VipsColourSpaceClass VipsCMC2LChClass;
+typedef VipsColourTransform VipsCMC2LCh;
+typedef VipsColourTransformClass VipsCMC2LChClass;
 
-G_DEFINE_TYPE( VipsCMC2LCh, vips_CMC2LCh, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsCMC2LCh, vips_CMC2LCh, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /* Generate LI (inverse) tables. 
  */
diff --git a/libvips/colour/XYZ2Lab.c b/libvips/colour/XYZ2Lab.c
index 06c420cf..9b86ce66 100644
--- a/libvips/colour/XYZ2Lab.c
+++ b/libvips/colour/XYZ2Lab.c
@@ -72,7 +72,7 @@
 float cbrt_table[QUANT_ELEMENTS];
 
 typedef struct _VipsXYZ2Lab {
-	VipsColourSpace parent_instance;
+	VipsColourTransform parent_instance;
 
 	/* The colour temperature -- default to D65. 
 	 */
@@ -86,9 +86,9 @@ typedef struct _VipsXYZ2Lab {
 
 } VipsXYZ2Lab;
 
-typedef VipsColourSpaceClass VipsXYZ2LabClass;
+typedef VipsColourTransformClass VipsXYZ2LabClass;
 
-G_DEFINE_TYPE( VipsXYZ2Lab, vips_XYZ2Lab, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsXYZ2Lab, vips_XYZ2Lab, VIPS_TYPE_COLOUR_TRANSFORM );
 
 static void *
 table_init( void *client )
diff --git a/libvips/colour/XYZ2Yxy.c b/libvips/colour/XYZ2Yxy.c
index 72dcfc5c..49194515 100644
--- a/libvips/colour/XYZ2Yxy.c
+++ b/libvips/colour/XYZ2Yxy.c
@@ -49,10 +49,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsXYZ2Yxy;
-typedef VipsColourSpaceClass VipsXYZ2YxyClass;
+typedef VipsColourTransform VipsXYZ2Yxy;
+typedef VipsColourTransformClass VipsXYZ2YxyClass;
 
-G_DEFINE_TYPE( VipsXYZ2Yxy, vips_XYZ2Yxy, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsXYZ2Yxy, vips_XYZ2Yxy, VIPS_TYPE_COLOUR_TRANSFORM );
 
 static void
 vips_XYZ2Yxy_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
diff --git a/libvips/colour/XYZ2scRGB.c b/libvips/colour/XYZ2scRGB.c
index 38bf4b4f..eccd4c09 100644
--- a/libvips/colour/XYZ2scRGB.c
+++ b/libvips/colour/XYZ2scRGB.c
@@ -47,10 +47,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsXYZ2scRGB;
-typedef VipsColourSpaceClass VipsXYZ2scRGBClass;
+typedef VipsColourTransform VipsXYZ2scRGB;
+typedef VipsColourTransformClass VipsXYZ2scRGBClass;
 
-G_DEFINE_TYPE( VipsXYZ2scRGB, vips_XYZ2scRGB, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsXYZ2scRGB, vips_XYZ2scRGB, VIPS_TYPE_COLOUR_TRANSFORM );
 
 /* We used to have the comment:
 
diff --git a/libvips/colour/Yxy2XYZ.c b/libvips/colour/Yxy2XYZ.c
index eca3d6e1..9289f349 100644
--- a/libvips/colour/Yxy2XYZ.c
+++ b/libvips/colour/Yxy2XYZ.c
@@ -49,10 +49,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsYxy2XYZ;
-typedef VipsColourSpaceClass VipsYxy2XYZClass;
+typedef VipsColourTransform VipsYxy2XYZ;
+typedef VipsColourTransformClass VipsYxy2XYZClass;
 
-G_DEFINE_TYPE( VipsYxy2XYZ, vips_Yxy2XYZ, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsYxy2XYZ, vips_Yxy2XYZ, VIPS_TYPE_COLOUR_TRANSFORM );
 
 void
 vips_Yxy2XYZ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
diff --git a/libvips/colour/colour.c b/libvips/colour/colour.c
index 27575838..0e15e44d 100644
--- a/libvips/colour/colour.c
+++ b/libvips/colour/colour.c
@@ -458,18 +458,19 @@ vips_colour_init( VipsColour *colour )
 	colour->input_bands = -1;
 }
 
-G_DEFINE_ABSTRACT_TYPE( VipsColourSpace, vips_colour_space, VIPS_TYPE_COLOUR );
+G_DEFINE_ABSTRACT_TYPE( VipsColourTransform, vips_colour_transform, 
+	VIPS_TYPE_COLOUR );
 
 static int
-vips_colour_space_build( VipsObject *object )
+vips_colour_transform_build( VipsObject *object )
 {
 	VipsColour *colour = VIPS_COLOUR( object );
-	VipsColourSpace *space = VIPS_COLOUR_SPACE( object );
+	VipsColourTransform *transform = VIPS_COLOUR_TRANSFORM( object );
 	VipsImage **t = (VipsImage **) vips_object_local_array( object, 1 );
 
 	/* We only process float.
 	 */
-	if( vips_cast_float( space->in, &t[0], NULL ) )
+	if( vips_cast_float( transform->in, &t[0], NULL ) )
 		return( -1 );
 
 	/* We always do 3 bands -> 3 bands. 
@@ -479,7 +480,7 @@ vips_colour_space_build( VipsObject *object )
 	colour->n = 1;
 	colour->in = t;
 
-	if( VIPS_OBJECT_CLASS( vips_colour_space_parent_class )->
+	if( VIPS_OBJECT_CLASS( vips_colour_transform_parent_class )->
 		build( object ) )
 		return( -1 );
 
@@ -487,7 +488,7 @@ vips_colour_space_build( VipsObject *object )
 }
 
 static void
-vips_colour_space_class_init( VipsColourSpaceClass *class )
+vips_colour_transform_class_init( VipsColourTransformClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
@@ -497,17 +498,17 @@ vips_colour_space_class_init( VipsColourSpaceClass *class )
 
 	vobject_class->nickname = "space";
 	vobject_class->description = _( "colour space transformations" );
-	vobject_class->build = vips_colour_space_build;
+	vobject_class->build = vips_colour_transform_build;
 
 	VIPS_ARG_IMAGE( class, "in", 1, 
 		_( "Input" ), 
 		_( "Input image" ),
 		VIPS_ARGUMENT_REQUIRED_INPUT, 
-		G_STRUCT_OFFSET( VipsColourSpace, in ) );
+		G_STRUCT_OFFSET( VipsColourTransform, in ) );
 }
 
 static void
-vips_colour_space_init( VipsColourSpace *space )
+vips_colour_transform_init( VipsColourTransform *space )
 {
 	VipsColour *colour = (VipsColour *) space; 
 
diff --git a/libvips/colour/dE00.c b/libvips/colour/dE00.c
index bdfe81de..3dfb304f 100644
--- a/libvips/colour/dE00.c
+++ b/libvips/colour/dE00.c
@@ -49,7 +49,7 @@ typedef struct _VipsdE00 {
 
 } VipsdE00;
 
-typedef VipsColourSpaceClass VipsdE00Class;
+typedef VipsColourDifferenceClass VipsdE00Class;
 
 G_DEFINE_TYPE( VipsdE00, vips_dE00, VIPS_TYPE_COLOUR_DIFFERENCE );
 
diff --git a/libvips/colour/dE76.c b/libvips/colour/dE76.c
index 47807aaa..b32595ba 100644
--- a/libvips/colour/dE76.c
+++ b/libvips/colour/dE76.c
@@ -54,7 +54,7 @@ typedef struct _VipsdE76 {
 
 } VipsdE76;
 
-typedef VipsColourSpaceClass VipsdE76Class;
+typedef VipsColourDifferenceClass VipsdE76Class;
 
 G_DEFINE_TYPE( VipsdE76, vips_dE76, VIPS_TYPE_COLOUR_DIFFERENCE );
 
diff --git a/libvips/colour/dECMC.c b/libvips/colour/dECMC.c
index d2454561..6aa8771f 100644
--- a/libvips/colour/dECMC.c
+++ b/libvips/colour/dECMC.c
@@ -47,7 +47,7 @@ typedef struct _VipsdECMC {
 
 } VipsdECMC;
 
-typedef VipsColourSpaceClass VipsdECMCClass;
+typedef VipsColourDifferenceClass VipsdECMCClass;
 
 G_DEFINE_TYPE( VipsdECMC, vips_dECMC, VIPS_TYPE_COLOUR_DIFFERENCE );
 
diff --git a/libvips/colour/pcolour.h b/libvips/colour/pcolour.h
index 4d9f4f6c..07b14967 100644
--- a/libvips/colour/pcolour.h
+++ b/libvips/colour/pcolour.h
@@ -98,34 +98,34 @@ GType vips_colour_get_type( void );
 /* A float in, float out colourspace transformation.
  */
 
-#define VIPS_TYPE_COLOUR_SPACE (vips_colour_space_get_type())
-#define VIPS_COLOUR_SPACE( obj ) \
+#define VIPS_TYPE_COLOUR_TRANSFORM (vips_colour_transform_get_type())
+#define VIPS_COLOUR_TRANSFORM( obj ) \
 	(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
-		VIPS_TYPE_COLOUR_SPACE, VipsColourSpace ))
-#define VIPS_COLOUR_SPACE_CLASS( klass ) \
+		VIPS_TYPE_COLOUR_TRANSFORM, VipsColourTransform ))
+#define VIPS_COLOUR_TRANSFORM_CLASS( klass ) \
 	(G_TYPE_CHECK_CLASS_CAST( (klass), \
-		VIPS_TYPE_COLOUR_SPACE, VipsColourSpaceClass))
-#define VIPS_IS_COLOUR_SPACE( obj ) \
-	(G_TYPE_CHECK_INSTANCE_TYPE( (obj), VIPS_TYPE_COLOUR_SPACE ))
-#define VIPS_IS_COLOUR_SPACE_CLASS( klass ) \
-	(G_TYPE_CHECK_CLASS_TYPE( (klass), VIPS_TYPE_COLOUR_SPACE ))
-#define VIPS_COLOUR_SPACE_GET_CLASS( obj ) \
+		VIPS_TYPE_COLOUR_TRANSFORM, VipsColourTransformClass))
+#define VIPS_IS_COLOUR_TRANSFORM( obj ) \
+	(G_TYPE_CHECK_INSTANCE_TYPE( (obj), VIPS_TYPE_COLOUR_TRANSFORM ))
+#define VIPS_IS_COLOUR_TRANSFORM_CLASS( klass ) \
+	(G_TYPE_CHECK_CLASS_TYPE( (klass), VIPS_TYPE_COLOUR_TRANSFORM ))
+#define VIPS_COLOUR_TRANSFORM_GET_CLASS( obj ) \
 	(G_TYPE_INSTANCE_GET_CLASS( (obj), \
-		VIPS_TYPE_COLOUR_SPACE, VipsColourSpaceClass ))
+		VIPS_TYPE_COLOUR_TRANSFORM, VipsColourTransformClass ))
 
-typedef struct _VipsColourSpace {
+typedef struct _VipsColourTransform {
 	VipsColour parent_instance;
 
 	VipsImage *in;
 
-} VipsColourSpace;
+} VipsColourTransform;
 
-typedef struct _VipsColourSpaceClass {
+typedef struct _VipsColourTransformClass {
 	VipsColourClass parent_class;
 
-} VipsColourSpaceClass;
+} VipsColourTransformClass;
 
-GType vips_colour_space_get_type( void );
+GType vips_colour_transform_get_type( void );
 
 /* Change colour encoding ... either in or out is not three-band float.
  */
diff --git a/libvips/colour/scRGB2XYZ.c b/libvips/colour/scRGB2XYZ.c
index b8d7e854..bf3750db 100644
--- a/libvips/colour/scRGB2XYZ.c
+++ b/libvips/colour/scRGB2XYZ.c
@@ -49,10 +49,10 @@
 
 #include "pcolour.h"
 
-typedef VipsColourSpace VipsscRGB2XYZ;
-typedef VipsColourSpaceClass VipsscRGB2XYZClass;
+typedef VipsColourTransform VipsscRGB2XYZ;
+typedef VipsColourTransformClass VipsscRGB2XYZClass;
 
-G_DEFINE_TYPE( VipsscRGB2XYZ, vips_scRGB2XYZ, VIPS_TYPE_COLOUR_SPACE );
+G_DEFINE_TYPE( VipsscRGB2XYZ, vips_scRGB2XYZ, VIPS_TYPE_COLOUR_TRANSFORM );
 
 void
 vips_scRGB2XYZ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )