diff --git a/ChangeLog b/ChangeLog
index 13a1426f..37b8355c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -61,6 +61,7 @@
 - vips7 binops all do sizealike too, also gbandjoin and ifthenelse
 - new API is now functional
 - vips.c generates GOption flags for vips8 operations
+- added im_gauss_dmask_sep()
 
 30/11/10 started 7.24.0
 - bump for new stable
diff --git a/libvips/include/vips/mask.h b/libvips/include/vips/mask.h
index 244a3967..db422c7e 100644
--- a/libvips/include/vips/mask.h
+++ b/libvips/include/vips/mask.h
@@ -82,6 +82,8 @@ INTMASK *im_gauss_imask_sep( const char *filename,
 	double sigma, double min_ampl );
 DOUBLEMASK *im_gauss_dmask( const char *filename, 
 	double sigma, double min_ampl );
+DOUBLEMASK *im_gauss_dmask_sep( const char *filename, 
+	double sigma, double min_ampl );
 
 INTMASK *im_dup_imask( INTMASK *in, const char *filename );
 DOUBLEMASK *im_dup_dmask( DOUBLEMASK *in, const char *filename );
diff --git a/libvips/mask/im_gaussmasks.c b/libvips/mask/im_gaussmasks.c
index d21754c0..36ad02fd 100644
--- a/libvips/mask/im_gaussmasks.c
+++ b/libvips/mask/im_gaussmasks.c
@@ -171,6 +171,46 @@ im_gauss_dmask( const char *filename, double sigma, double min_ampl )
 	return( m );
 }
 
+/**
+ * im_gauss_dmask_sep:
+ * @filename: the returned mask has this set as the filename
+ * @sigma: standard deviation of mask
+ * @min_ampl: minimum amplitude
+ *
+ * im_gauss_dmask_sep() works exactly as im_gauss_dmask(), but returns only
+ * the central line of the mask. This is useful with im_convsepf().
+ *
+ * See also: im_gauss_dmask(), im_convsepf().
+ *
+ * Returns: the calculated mask on success, or NULL on error.
+ */
+DOUBLEMASK *
+im_gauss_dmask_sep( const char *filename, double sigma, double min_ampl )
+{
+	DOUBLEMASK *im;
+	DOUBLEMASK *im2;
+	int i;
+	double sum;
+
+	if( !(im = im_gauss_dmask( filename, sigma, min_ampl )) )
+		return( NULL );
+	if( !(im2 = im_create_dmask( filename, im->xsize, 1 )) ) {
+		im_free_dmask( im );
+		return( NULL );
+	}
+
+	sum = 0;
+	for( i = 0; i < im->xsize; i++ ) {
+		im2->coeff[i] = im->coeff[i + im->xsize * (im->ysize / 2)];
+		sum += im2->coeff[i];
+	}
+	im2->scale = sum;
+
+	im_free_dmask( im );
+
+	return( im2 );
+}
+
 /**
  * im_gauss_imask:
  * @filename: the returned mask has this set as the filename
diff --git a/libvips/mask/mask_dispatch.c b/libvips/mask/mask_dispatch.c
index ea011e7a..d7c4e298 100644
--- a/libvips/mask/mask_dispatch.c
+++ b/libvips/mask/mask_dispatch.c
@@ -229,6 +229,33 @@ static im_function gauss_dmask_desc = {
 	gauss_dmask_args 		/* Arg list */
 };
 
+/* Call im_gauss_dmask_sep via arg vector.
+ */
+static int
+gauss_dmask_sep_vec( im_object *argv )
+{
+	im_mask_object *mo = argv[0];
+	double sigma = *((double *) argv[1]);
+	double min_amp = *((double *) argv[2]);
+
+	if( !(mo->mask = 
+		im_gauss_dmask_sep( mo->name, sigma, min_amp )) )
+		return( -1 );
+	
+	return( 0 );
+}
+
+/* Description of im_gauss_dmask_sep.
+ */ 
+static im_function gauss_dmask_sep_desc = {
+	"im_gauss_dmask_sep", 		/* Name */
+	"generate separable gaussian DOUBLEMASK",
+	0,				/* Flags */
+	gauss_dmask_sep_vec, 		/* Dispatch function */
+	IM_NUMBER( gauss_dmask_args ), 	/* Size of arg list */
+	gauss_dmask_args 		/* Arg list */
+};
+
 /* Args for im_gauss_imask.
  */
 static im_arg_desc gauss_imask_args[] = {
@@ -549,6 +576,7 @@ static im_function dmask_ysize_desc = {
  */
 static im_function *mask_list[] = {
 	&gauss_dmask_desc,
+	&gauss_dmask_sep_desc,
 	&log_dmask_desc,
 	&log_imask_desc,
 	&gauss_imask_desc,