diff --git a/libvips/colour/XYZ2CMYK.c b/libvips/colour/XYZ2CMYK.c
index 6d03a7f1..4c8baac2 100644
--- a/libvips/colour/XYZ2CMYK.c
+++ b/libvips/colour/XYZ2CMYK.c
@@ -3,6 +3,8 @@
  *
  * 21/12/18
  *      - from CMYK2XYZ.c
+ * 09/01/2019
+ *  	- add CMYK <-> XYZ conversions if no lcms2 has been found
  */
 
 /*
diff --git a/libvips/colour/colourspace.c b/libvips/colour/colourspace.c
index 2af6bfbf..3779ce6f 100644
--- a/libvips/colour/colourspace.c
+++ b/libvips/colour/colourspace.c
@@ -21,8 +21,6 @@
  * 	  https://github.com/lovell/sharp/issues/193
  * 27/12/18
  * 	- add CMYK conversions
- * 09/01/2019
- *  - add CMYK <-> XYZ conversions if no lcms2 has been found
  */
 
 /*
diff --git a/libvips/resample/thumbnail.c b/libvips/resample/thumbnail.c
index 8d386e78..20790e1c 100644
--- a/libvips/resample/thumbnail.c
+++ b/libvips/resample/thumbnail.c
@@ -599,8 +599,14 @@ vips_thumbnail_build( VipsObject *object )
 		have_imported = TRUE;
 	}
 
-	/* To the processing colourspace. This will unpack LABQ as well.
+	/* To the processing colourspace. This will unpack LABQ, import CMYK,
+	 * etc.
+	 *
+	 * If this is a CMYK image, we need to set have_imported since we only
+	 * want to export at the end.
 	 */
+	if( in->Type == VIPS_INTERPRETATION_CMYK )
+		have_imported = TRUE;
 	g_info( "converting to processing space %s",
 		vips_enum_nick( VIPS_TYPE_INTERPRETATION, interpretation ) ); 
 	if( vips_colourspace( in, &t[2], interpretation, NULL ) )