diff --git a/TODO b/TODO
index e10430cf..6f2baf09 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,5 @@
+- add a convf test
+
 - add more webp tests to py suite
 
 - try moving some more of the CLI tests to py
diff --git a/libvips/convolution/Makefile.am b/libvips/convolution/Makefile.am
index 67ff955c..f069548c 100644
--- a/libvips/convolution/Makefile.am
+++ b/libvips/convolution/Makefile.am
@@ -15,7 +15,6 @@ libconvolution_la_SOURCES = \
 	gaussblur.c \
 	im_aconv.c \
 	im_aconvsep.c \
-	im_conv.c \
-	im_conv_f.c 
+	im_conv.c 
 
 AM_CPPFLAGS = -I${top_srcdir}/libvips/include @VIPS_CFLAGS@ @VIPS_INCLUDES@ 
diff --git a/libvips/convolution/conv.c b/libvips/convolution/conv.c
index e795c2fd..d34ec6b1 100644
--- a/libvips/convolution/conv.c
+++ b/libvips/convolution/conv.c
@@ -73,11 +73,11 @@ vips_conv_build( VipsObject *object )
 	INTMASK *imsk;
 	DOUBLEMASK *dmsk;
 
-	g_object_set( conv, "out", vips_image_new(), NULL ); 
-
 	if( VIPS_OBJECT_CLASS( vips_conv_parent_class )->build( object ) )
 		return( -1 );
 
+	g_object_set( conv, "out", vips_image_new(), NULL ); 
+
 	in = convolution->in;
 
 	/*
@@ -99,13 +99,14 @@ vips_conv_build( VipsObject *object )
 	in = t[0];
 
 	switch( conv->precision ) { 
-	case VIPS_PRECISION_INTEGER:
-		if( im_conv( in, convolution->out, imsk ) )
+	case VIPS_PRECISION_FLOAT:
+		if( vips_convf( in, &t[1], convolution->M, NULL ) ||
+			vips_image_write( t[1], convolution->out ) )
 			return( -1 ); 
 		break;
 
-	case VIPS_PRECISION_FLOAT:
-		if( im_conv_f( in, convolution->out, dmsk ) )
+	case VIPS_PRECISION_INTEGER:
+		if( im_conv( in, convolution->out, imsk ) )
 			return( -1 ); 
 		break;
 
diff --git a/libvips/convolution/convf.c b/libvips/convolution/convf.c
index 4e690cbd..be7b59b2 100644
--- a/libvips/convolution/convf.c
+++ b/libvips/convolution/convf.c
@@ -1,4 +1,4 @@
-/* im_conv_f
+/* convf
  *
  * Copyright: 1990, N. Dessipris.
  *
@@ -276,7 +276,6 @@ vips_convf_gen( REGION *or, void *vseq, void *a, void *b, gboolean *stop )
 static int
 vips_convf_build( VipsObject *object )
 {
-	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
 	VipsConvolution *convolution = (VipsConvolution *) object;
 	VipsConvf *convf = (VipsConvf *) object;
 	VipsImage **t = (VipsImage **) vips_object_local_array( object, 4 );
@@ -354,11 +353,10 @@ vips_convf_build( VipsObject *object )
 static void
 vips_convf_class_init( VipsConvfClass *class )
 {
-	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *object_class = (VipsObjectClass *) class;
 
 	object_class->nickname = "convf";
-	object_class->description = _( "convolution operation, float" );
+	object_class->description = _( "float convolution operation" );
 	object_class->build = vips_convf_build;
 }
 
diff --git a/libvips/convolution/im_conv_f.c b/libvips/convolution/im_conv_f.c
deleted file mode 100644
index 0cbe104b..00000000
--- a/libvips/convolution/im_conv_f.c
+++ /dev/null
@@ -1,389 +0,0 @@
-/* im_conv_f
- *
- * Copyright: 1990, N. Dessipris.
- *
- * Author: Nicos Dessipris & Kirk Martinez
- * Written on: 29/04/1991
- * Modified on: 19/05/1991
- * 8/7/93 JC
- *      - adapted for partial v2
- *      - memory leaks fixed
- *      - ANSIfied
- * 12/7/93 JC
- *	- adapted im_convbi() to im_convbf()
- * 7/10/94 JC
- *	- new IM_ARRAY() macro
- *	- evalend callbacks
- *	- more typedef
- * 9/3/01 JC
- *	- redone from im_conv() 
- * 27/7/01 JC
- *	- rejects masks with scale == 0
- * 7/4/04 
- *	- now uses im_embed() with edge stretching on the input, not
- *	  the output
- *	- sets Xoffset / Yoffset
- * 11/11/05
- * 	- simpler inner loop avoids gcc4 bug 
- * 12/11/09
- * 	- only rebuild the buffer offsets if bpl changes
- * 	- tiny speedups and cleanups
- * 	- add restrict, though it doesn't seem to help gcc
- * 	- add mask-all-zero check
- * 13/11/09
- * 	- rename as im_conv_f() to make it easier for vips.c to make the
- * 	  overloaded version
- * 3/2/10
- * 	- gtkdoc
- * 	- more cleanups
- * 1/10/10
- * 	- support complex (just double the bands)
- * 29/10/10
- * 	- get rid of im_convsep_f(), just call this twice, no longer worth
- * 	  keeping two versions
- * 15/10/11 Nicolas
- * 	- handle offset correctly in seperable convolutions
- * 26/1/16 Lovell Fuller
- * 	- remove Duff for a 25% speedup
- */
-
-/*
-
-    This file is part of VIPS.
-    
-    VIPS is free software; you can redistribute it and/or modify
-    it under the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-    02110-1301  USA
-
- */
-
-/*
-
-    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
-
- */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif /*HAVE_CONFIG_H*/
-#include <vips/intl.h>
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <limits.h>
-
-#include <vips/vips.h>
-
-/* Our parameters ... we take a copy of the mask argument, plus we make a
- * smaller version with the zeros squeezed out. 
- */
-typedef struct {
-	IMAGE *in;
-	IMAGE *out;
-	DOUBLEMASK *mask;	/* Copy of mask arg */
-
-	int nnz;		/* Number of non-zero mask elements */
-	double *coeff;		/* Array of non-zero mask coefficients */
-	int *coeff_pos;		/* Index of each nnz element in mask->coeff */
-} Conv;
-
-static int
-conv_close( Conv *conv )
-{
-	IM_FREEF( im_free_dmask, conv->mask );
-
-        return( 0 );
-}
-
-static Conv *
-conv_new( IMAGE *in, IMAGE *out, DOUBLEMASK *mask )
-{
-        Conv *conv = IM_NEW( out, Conv );
-	const int ne = mask->xsize * mask->ysize;
-        int i;
-
-        if( !conv )
-                return( NULL );
-
-        conv->in = in;
-        conv->out = out;
-        conv->mask = NULL;
-        conv->nnz = 0;
-        conv->coeff = NULL;
-
-        if( im_add_close_callback( out, 
-		(im_callback_fn) conv_close, conv, NULL ) ||
-        	!(conv->coeff = IM_ARRAY( out, ne, double )) ||
-        	!(conv->coeff_pos = IM_ARRAY( out, ne, int )) ||
-        	!(conv->mask = im_dup_dmask( mask, "conv_mask" )) )
-                return( NULL );
-
-        /* Find non-zero mask elements.
-         */
-        for( i = 0; i < ne; i++ )
-                if( mask->coeff[i] ) {
-			conv->coeff[conv->nnz] = mask->coeff[i];
-			conv->coeff_pos[conv->nnz] = i;
-			conv->nnz += 1;
-		}
-
-	/* Was the whole mask zero? We must have at least 1 element in there:
-	 * set it to zero.
-	 */
-	if( conv->nnz == 0 ) {
-		conv->coeff[0] = mask->coeff[0];
-		conv->coeff_pos[0] = 0;
-		conv->nnz = 1;
-	}
-
-        return( conv );
-}
-
-/* Our sequence value.
- */
-typedef struct {
-	Conv *conv;
-	REGION *ir;		/* Input region */
-
-	int *offsets;		/* Offsets for each non-zero matrix element */
-	VipsPel **pts;		/* Per-non-zero mask element image pointers */
-
-	int last_bpl;		/* Avoid recalcing offsets, if we can */
-} ConvSequence;
-
-/* Free a sequence value.
- */
-static int
-conv_stop( void *vseq, void *a, void *b )
-{
-	ConvSequence *seq = (ConvSequence *) vseq;
-
-	IM_FREEF( im_region_free, seq->ir );
-
-	return( 0 );
-}
-
-/* Convolution start function.
- */
-static void *
-conv_start( IMAGE *out, void *a, void *b )
-{
-	IMAGE *in = (IMAGE *) a;
-	Conv *conv = (Conv *) b;
-	ConvSequence *seq;
-
-	if( !(seq = IM_NEW( out, ConvSequence )) )
-		return( NULL );
-
-	/* Init!
-	 */
-	seq->conv = conv;
-	seq->ir = NULL;
-	seq->pts = NULL;
-	seq->last_bpl = -1;
-
-	/* Attach region and arrays.
-	 */
-	seq->ir = im_region_create( in );
-	seq->offsets = IM_ARRAY( out, conv->nnz, int );
-	seq->pts = IM_ARRAY( out, conv->nnz, VipsPel * );
-	if( !seq->ir || !seq->offsets || !seq->pts ) {
-		conv_stop( seq, in, conv );
-		return( NULL );
-	}
-
-	return( (void *) seq );
-}
-
-#define CONV_FLOAT( ITYPE, OTYPE ) { \
-	ITYPE ** restrict p = (ITYPE **) seq->pts; \
-	OTYPE * restrict q = (OTYPE *) IM_REGION_ADDR( or, le, y ); \
-	\
-	for( x = 0; x < sz; x++ ) {  \
-		double sum; \
-		int i; \
-		\
-		sum = 0; \
-		for ( i = 0; i < nnz; i++ ) \
-			sum += t[i] * p[i][x]; \
- 		\
-		sum = (sum / mask->scale) + mask->offset; \
-		\
-		q[x] = sum;  \
-	}  \
-} 
-
-/* Convolve!
- */
-static int
-conv_gen( REGION *or, void *vseq, void *a, void *b )
-{
-	ConvSequence *seq = (ConvSequence *) vseq;
-	IMAGE *in = (IMAGE *) a;
-	Conv *conv = (Conv *) b;
-	REGION *ir = seq->ir;
-	DOUBLEMASK *mask = conv->mask;
-	double * restrict t = conv->coeff; 
-	const int nnz = conv->nnz;
-
-	Rect *r = &or->valid;
-	Rect s;
-	int le = r->left;
-	int to = r->top;
-	int bo = IM_RECT_BOTTOM(r);
-	int sz = IM_REGION_N_ELEMENTS( or ) * 
-		(vips_band_format_iscomplex( in->BandFmt ) ? 2 : 1);
-
-	int x, y, z, i;
-
-	/* Prepare the section of the input image we need. A little larger
-	 * than the section of the output image we are producing.
-	 */
-	s = *r;
-	s.width += mask->xsize - 1;
-	s.height += mask->ysize - 1;
-	if( im_prepare( ir, &s ) )
-		return( -1 );
-
-        /* Fill offset array. Only do this if the bpl has changed since the 
-	 * previous im_prepare().
-	 */
-	if( seq->last_bpl != IM_REGION_LSKIP( ir ) ) {
-		seq->last_bpl = IM_REGION_LSKIP( ir );
-
-		for( i = 0; i < nnz; i++ ) {
-			z = conv->coeff_pos[i];
-			x = z % conv->mask->xsize;
-			y = z / conv->mask->xsize;
-
-			seq->offsets[i] = 
-				IM_REGION_ADDR( ir, x + le, y + to ) -
-				IM_REGION_ADDR( ir, le, to );
-		}
-	}
-
-	for( y = to; y < bo; y++ ) { 
-		/* Init pts for this line of PELs.
-		 */
-		for( z = 0; z < nnz; z++ )
-			seq->pts[z] = seq->offsets[z] +
-				IM_REGION_ADDR( ir, le, y ); 
-
-		switch( in->BandFmt ) {
-		case IM_BANDFMT_UCHAR: 	
-			CONV_FLOAT( unsigned char, float ); break;
-		case IM_BANDFMT_CHAR:   
-			CONV_FLOAT( signed char, float ); break;
-		case IM_BANDFMT_USHORT: 
-			CONV_FLOAT( unsigned short, float ); break;
-		case IM_BANDFMT_SHORT:  
-			CONV_FLOAT( signed short, float ); break;
-		case IM_BANDFMT_UINT:   
-			CONV_FLOAT( unsigned int, float ); break;
-		case IM_BANDFMT_INT:    
-			CONV_FLOAT( signed int, float ); break;
-		case IM_BANDFMT_FLOAT:  
-		case IM_BANDFMT_COMPLEX:  
-			CONV_FLOAT( float, float ); break;
-		case IM_BANDFMT_DOUBLE: 
-		case IM_BANDFMT_DPCOMPLEX:  
-			CONV_FLOAT( double, double ); break;
-
-		default:
-			g_assert_not_reached();
-		}
-	}
-
-	return( 0 );
-}
-
-int
-im_conv_f_raw( IMAGE *in, IMAGE *out, DOUBLEMASK *mask )
-{
-	Conv *conv;
-
-	/* Check parameters.
-	 */
-	if( im_piocheck( in, out ) ||
-		im_check_uncoded( "im_conv", in ) ||
-		im_check_dmask( "im_conv", mask ) ) 
-		return( -1 );
-	if( mask->scale == 0 ) {
-		im_error( "im_conv_f", "%s", "mask scale must be non-zero" );
-		return( -1 );
-	}
-	if( !(conv = conv_new( in, out, mask )) )
-		return( -1 );
-
-	/* Prepare output. Consider a 7x7 mask and a 7x7 image --- the output
-	 * would be 1x1.
-	 */
-	if( im_cp_desc( out, in ) )
-		return( -1 );
-	if( vips_bandfmt_isint( in->BandFmt ) ) 
-		out->BandFmt = IM_BANDFMT_FLOAT;
-	out->Xsize -= mask->xsize - 1;
-	out->Ysize -= mask->ysize - 1;
-	if( out->Xsize <= 0 || out->Ysize <= 0 ) {
-		im_error( "im_conv_f", "%s", _( "image too small for mask" ) );
-		return( -1 );
-	}
-
-	if( im_demand_hint( out, IM_SMALLTILE, in, NULL ) )
-		return( -1 );
-
-	if( im_generate( out, conv_start, conv_gen, conv_stop, in, conv ) )
-		return( -1 );
-
-	out->Xoffset = -mask->xsize / 2;
-	out->Yoffset = -mask->ysize / 2;
-
-	return( 0 );
-}
-
-/**
- * im_conv_f:
- * @in: input image
- * @out: output image
- * @mask: convolution mask
- *
- * Convolve @in with @mask using floating-point arithmetic. The output image 
- * is always %IM_BANDFMT_FLOAT unless @in is %IM_BANDFMT_DOUBLE, in which case
- * @out is also %IM_BANDFMT_DOUBLE. 
- *
- * Each output pixel is
- * calculated as sigma[i]{pixel[i] * mask[i]} / scale + offset, where scale
- * and offset are part of @mask. 
- *
- * See also: im_conv(), im_convsep_f(), im_create_dmaskv().
- *
- * Returns: 0 on success, -1 on error
- */
-int 
-im_conv_f( IMAGE *in, IMAGE *out, DOUBLEMASK *mask )
-{
-	IMAGE *t1 = im_open_local( out, "im_conv_f intermediate", "p" );
-
-	if( !t1 || 
-		im_embed( in, t1, 1, mask->xsize / 2, mask->ysize / 2, 
-			in->Xsize + mask->xsize - 1, 
-			in->Ysize + mask->ysize - 1 ) ||
-		im_conv_f_raw( t1, out, mask ) )
-		return( -1 );
-
-	out->Xoffset = 0;
-	out->Yoffset = 0;
-
-	return( 0 );
-}
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index 18713e38..009178d8 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -2404,6 +2404,36 @@ im_convsep_f( IMAGE *in, IMAGE *out, DOUBLEMASK *mask )
 	return( 0 );
 }
 
+int 
+im_conv_f( VipsImage *in, VipsImage *out, DOUBLEMASK *mask )
+{
+	VipsImage *t1, *t2;
+
+	if( !(t1 = vips_image_new()) ||
+		im_mask2vips( mask, t1 ) )
+		return( -1 );
+	if( vips_convf( in, &t2, t1, 
+		NULL ) ) {
+		g_object_unref( t1 );
+		return( -1 );
+	}
+	g_object_unref( t1 );
+	if( vips_image_write( t2, out ) ) {
+		g_object_unref( t2 );
+		return( -1 );
+	}
+	g_object_unref( t2 );
+
+	return( 0 );
+}
+
+int
+im_conv_f_raw( VipsImage *in, VipsImage *out, DOUBLEMASK *mask )
+{
+	im_error( "im_conv_f_raw", "no compat function" );
+	return( -1 );
+}
+
 int
 im_addgnoise( IMAGE *in, IMAGE *out, double sigma )
 {