diff --git a/libvips/foreign/Makefile.am b/libvips/foreign/Makefile.am
index b44cf53c..30f392c4 100644
--- a/libvips/foreign/Makefile.am
+++ b/libvips/foreign/Makefile.am
@@ -16,7 +16,6 @@ libforeign_la_SOURCES = \
 	radiance.c \
 	radload.c \
 	radsave.c \
-	ppm.c \
 	ppmload.c \
 	ppmsave.c \
 	csv.c \
diff --git a/libvips/foreign/dzsave.c b/libvips/foreign/dzsave.c
index 6d6ec536..3f3000f3 100644
--- a/libvips/foreign/dzsave.c
+++ b/libvips/foreign/dzsave.c
@@ -1135,22 +1135,7 @@ build_scan_properties( VipsImage *image )
 	char *date;
 	int i;
 
-#ifdef HAVE_DATE_TIME_FORMAT_ISO8601
-{
-	GDateTime *now;
-
-	now = g_date_time_new_now_local();
-	date = g_date_time_format_iso8601( now );
-	g_date_time_unref( now );
-}
-#else /*!HAVE_DATE_TIME_FORMAT_ISO8601*/
-{
-	GTimeVal now;
-
-	g_get_current_time( &now );
-	date = g_time_val_to_iso8601( &now );
-}
-#endif /*HAVE_DATE_TIME_FORMAT_ISO8601*/
+	date = vips__get_iso8601();
 
 	vips_dbuf_init( &dbuf );
 	vips_dbuf_writef( &dbuf, "<?xml version=\"1.0\"?>\n" ); 
diff --git a/libvips/foreign/foreign.c b/libvips/foreign/foreign.c
index 9d8ca8c5..129dd1b9 100644
--- a/libvips/foreign/foreign.c
+++ b/libvips/foreign/foreign.c
@@ -1993,7 +1993,7 @@ vips_foreign_operation_init( void )
 	extern GType vips_foreign_save_rad_stream_get_type( void ); 
 	extern GType vips_foreign_load_mat_get_type( void ); 
 	extern GType vips_foreign_load_ppm_file_get_type( void ); 
-	extern GType vips_foreign_save_ppm_get_type( void ); 
+	extern GType vips_foreign_save_ppm_file_get_type( void ); 
 	extern GType vips_foreign_load_png_get_type( void ); 
 	extern GType vips_foreign_load_png_buffer_get_type( void ); 
 	extern GType vips_foreign_load_png_stream_get_type( void ); 
@@ -2077,7 +2077,7 @@ vips_foreign_operation_init( void )
 
 #ifdef HAVE_PPM
 	vips_foreign_load_ppm_file_get_type(); 
-	vips_foreign_save_ppm_get_type(); 
+	vips_foreign_save_ppm_file_get_type(); 
 #endif /*HAVE_PPM*/
 
 #ifdef HAVE_RADIANCE
diff --git a/libvips/foreign/ppm.c b/libvips/foreign/ppm.c
deleted file mode 100644
index d8450d86..00000000
--- a/libvips/foreign/ppm.c
+++ /dev/null
@@ -1,330 +0,0 @@
-/* Read a ppm file.
- * 
-
- * 4/2/10
- * 	- gtkdoc
-
- * 13/11/19
- * 	- redone with streams
- */
-
-/*
-
-    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>
-
-#ifdef HAVE_PPM
-
-#include <ctype.h>
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <math.h>
-#include <errno.h>
-
-#include <vips/vips.h>
-#include <vips/internal.h>
-
-#include "pforeign.h"
-
-struct _Write;
-
-typedef int (*write_fn)( struct _Write *write, VipsPel *p );
-
-/* What we track during a PPM write.
- */
-typedef struct _Write {
-	VipsImage *in;
-	VipsStreamo *streamo;
-	write_fn fn;
-} Write;
-
-static void
-write_destroy( Write *write )
-{
-	if( write->streamo ) 
-		vips_streamo_finish( write->streamo );
-	VIPS_UNREF( write->streamo );
-
-	vips_free( write );
-}
-
-static Write *
-write_new( VipsImage *in, VipsStreamo *streamo )
-{
-	Write *write;
-
-	if( !(write = VIPS_NEW( NULL, Write )) )
-		return( NULL );
-
-	write->in = in;
-        write->streamo = streamo;
-	g_object_ref( streamo );
-        write->fn = NULL;
-
-        return( write );
-}
-
-static int
-write_ppm_line_ascii( Write *write, VipsPel *p )
-{
-	const int sk = VIPS_IMAGE_SIZEOF_PEL( write->in );
-	int x, k;
-
-	for( x = 0; x < write->in->Xsize; x++ ) {
-		for( k = 0; k < write->in->Bands; k++ ) {
-			switch( write->in->BandFmt ) {
-			case VIPS_FORMAT_UCHAR:
-				vips_streamo_writef( write->streamo, 
-					"%d ", p[k] );
-				break;
-
-			case VIPS_FORMAT_USHORT:
-				vips_streamo_writef( write->streamo, 
-					"%d ", ((unsigned short *) p)[k] );
-				break;
-
-			case VIPS_FORMAT_UINT:
-				vips_streamo_writef( write->streamo, 
-					"%d ", ((unsigned int *) p)[k] );
-				break;
-
-			default:
-				g_assert_not_reached();
-			}
-		}
-
-		p += sk;
-	}
-
-	if( vips_streamo_writef( write->streamo, "\n" ) ) 
-		return( -1 );
-
-	return( 0 );
-}
-
-static int
-write_ppm_line_ascii_squash( Write *write, VipsPel *p )
-{
-	int x;
-
-	for( x = 0; x < write->in->Xsize; x++ ) 
-		vips_streamo_writef( write->streamo, "%d ", p[x] ? 0 : 1 );
-
-	if( vips_streamo_writef( write->streamo, "\n" ) ) 
-		return( -1 );
-
-	return( 0 );
-}
-
-static int
-write_ppm_line_binary( Write *write, VipsPel *p )
-{
-	if( vips_streamo_write( write->streamo, 
-		p, VIPS_IMAGE_SIZEOF_LINE( write->in ) ) ) 
-		return( -1 );
-
-	return( 0 );
-}
-
-static int
-write_ppm_line_binary_squash( Write *write, VipsPel *p )
-{
-	int x;
-	int bits;
-	int n_bits;
-
-	bits = 0;
-	n_bits = 0;
-	for( x = 0; x < write->in->Xsize; x++ ) {
-		bits = VIPS_LSHIFT_INT( bits, 1 );
-		n_bits += 1;
-		bits |= p[x] ? 0 : 1;
-
-		if( n_bits == 8 ) {
-			if( VIPS_STREAMO_PUTC( write->streamo, bits ) ) 
-				return( -1 );
-
-			bits = 0;
-			n_bits = 0;
-		}
-	}
-
-	/* Flush any remaining bits in this line.
-	 */
-	if( n_bits &&
-		VIPS_STREAMO_PUTC( write->streamo, bits ) ) 
-		return( -1 );
-
-	return( 0 );
-}
-
-static int
-write_ppm_block( VipsRegion *region, VipsRect *area, void *a )
-{
-	Write *write = (Write *) a;
-	int i;
-
-	for( i = 0; i < area->height; i++ ) {
-		VipsPel *p = VIPS_REGION_ADDR( region, 0, area->top + i );
-
-		if( write->fn( write, p ) )
-			return( -1 );
-	}
-
-	return( 0 );
-}
-
-static int
-write_ppm( Write *write, gboolean ascii, gboolean squash ) 
-{
-	VipsImage *in = write->in;
-
-	char *magic;
-	time_t timebuf;
-
-	magic = "unset";
-	if( in->BandFmt == VIPS_FORMAT_FLOAT && in->Bands == 3 ) 
-		magic = "PF";
-	else if( in->BandFmt == VIPS_FORMAT_FLOAT && in->Bands == 1 ) 
-		magic = "Pf";
-	else if( in->Bands == 1 && ascii && squash )
-		magic = "P1";
-	else if( in->Bands == 1 && ascii )
-		magic = "P2";
-	else if( in->Bands == 1 && !ascii && squash )
-		magic = "P4";
-	else if( in->Bands == 1 && !ascii )
-		magic = "P5";
-	else if( in->Bands == 3 && ascii )
-		magic = "P3";
-	else if( in->Bands == 3 && !ascii )
-		magic = "P6";
-	else
-		g_assert_not_reached();
-
-	vips_streamo_writef( write->streamo, "%s\n", magic );
-	time( &timebuf );
-	vips_streamo_writef( write->streamo, 
-		"#vips2ppm - %s\n", ctime( &timebuf ) );
-	vips_streamo_writef( write->streamo, "%d %d\n", in->Xsize, in->Ysize );
-
-	if( !squash ) 
-		switch( in->BandFmt ) {
-		case VIPS_FORMAT_UCHAR:
-			vips_streamo_writef( write->streamo, 
-				"%d\n", UCHAR_MAX );
-			break;
-
-		case VIPS_FORMAT_USHORT:
-			vips_streamo_writef( write->streamo, 
-				"%d\n", USHRT_MAX );
-			break;
-
-		case VIPS_FORMAT_UINT:
-			vips_streamo_writef( write->streamo, 
-				"%d\n", UINT_MAX );
-			break;
-
-		case VIPS_FORMAT_FLOAT:
-{
-			double scale;
-
-			if( vips_image_get_double( in, "pfm-scale", &scale ) )
-				scale = 1;
-			if( !vips_amiMSBfirst() )
-				scale *= -1;
-			vips_streamo_writef( write->streamo, 
-				"%g\n", scale );
-}
-			break;
-
-		default:
-			g_assert_not_reached();
-		}
-
-	if( squash )
-		write->fn = ascii ? 
-			write_ppm_line_ascii_squash : 
-			write_ppm_line_binary_squash;
-	else
-		write->fn = ascii ? 
-			write_ppm_line_ascii : 
-			write_ppm_line_binary;
-
-	if( vips_sink_disc( write->in, write_ppm_block, write ) )
-		return( -1 );
-
-	return( 0 );
-}
-
-int
-vips__ppm_save_stream( VipsImage *in, VipsStreamo *streamo,
-	gboolean ascii, gboolean squash )
-{
-	Write *write;
-
-	if( vips_check_uintorf( "vips2ppm", in ) || 
-		vips_check_bands_1or3( "vips2ppm", in ) || 
-		vips_check_uncoded( "vips2ppm", in ) || 
-		vips_image_pio_input( in ) )
-		return( -1 );
-
-	if( ascii && 
-		in->BandFmt == VIPS_FORMAT_FLOAT ) {
-		g_warning( "%s", 
-			_( "float images must be binary -- disabling ascii" ) );
-		ascii = FALSE;
-	}
-
-	/* One bit images must come from a 8 bit, one band source. 
-	 */
-	if( squash && 
-		(in->Bands != 1 || 
-		 in->BandFmt != VIPS_FORMAT_UCHAR) ) {
-		g_warning( "%s", 
-			_( "can only squash 1 band uchar images -- " 
-				"disabling squash" ) );
-		squash = FALSE; 
-	}
-
-	if( !(write = write_new( in, streamo )) )
-		return( -1 );
-
-	if( write_ppm( write, ascii, squash ) ) {
-		write_destroy( write );
-		return( -1 );
-	}
-	write_destroy( write );
-
-	return( 0 );
-}
-
-#endif /*HAVE_PPM*/
diff --git a/libvips/foreign/ppmload.c b/libvips/foreign/ppmload.c
index c2d08d34..50365785 100644
--- a/libvips/foreign/ppmload.c
+++ b/libvips/foreign/ppmload.c
@@ -62,6 +62,12 @@
 
  */
 
+/* TODO
+ *
+ * - make partial
+ * - only use mmap on filename streams?
+ */
+
 /*
 #define DEBUG
  */
@@ -147,110 +153,32 @@ vips_foreign_load_ppm_is_a_stream( VipsStreami *streami )
 	return( FALSE );
 }
 
-/* The largest number/field/whatever we can read.
- */
-#define MAX_THING (80)
-
-/* After this, the next getc will be the first char of the next line (or EOF).
- */
-static int 
-skip_line( VipsStreamib *streamib )
-{
-	int ch;
-
-        while( (ch = VIPS_STREAMIB_GETC( streamib )) != '\n' && 
-		ch != EOF )
-		;
-
-	if( ch == EOF )
-		return( -1 );
-
-	return( 0 );
-}
-
-/* After this, the next getc will be the first char of the next block of
- * non-whitespace (or EOF).
- */
-static int 
-skip_white_space( VipsStreamib *streamib )
-{
-        int ch;
-
-	while( isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) )
-		;
-	VIPS_STREAMIB_UNGETC( streamib );
-
-	/* # skip comments too.
-	 */
-	if( ch == '#' &&
-		(skip_line( streamib ) ||
-		 skip_white_space( streamib )) )
-		return( -1 );
-
-	return( 0 );
-}
-
-/* After this, the next getc will be the first char of the next block of
- * whitespace (or EOF). buf will be filled with up to length bytes, and
- * null-terminated.
- *
- * If the first getc is whitespace, stop instantly and return nothing.
- */
 static int
-read_non_white_space( VipsStreamib *streamib, char *buf, int length )
+get_int( VipsStreamib *streamib, int *i )
 {
-	int ch;
-	int i;
+	const char *txt;
 
-	for( i = 0; i < length - 1 &&
-		!isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) &&
-		ch != EOF; i++ ) 
-		buf[i] = ch;
-	buf[i] = '\0';
+	if( vips_streamib_skip_whitespace( streamib ) ||
+		!(txt = vips_streamib_get_non_whitespace( streamib )) )
+		return( -1 );
 
-	/* If we stopped before seeing any whitespace, skip to the end of the
-	 * block of non-whitespace.
-	 */
-	if( !isspace( ch ) ) 
-		while( !isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) &&
-			ch != EOF )
-			;
-
-	/* If we finally stopped on whitespace, step back one so the next get
-	 * will be whitespace (or EOF).
-	 */
-	if( isspace( ch ) ) 
-		VIPS_STREAMIB_UNGETC( streamib );
+	*i = atoi( txt ); 
 
 	return( 0 );
 }
 
 static int
-read_int( VipsStreamib *streamib, int *i )
+get_float( VipsStreamib *streamib, float *f )
 {
-	char buf[MAX_THING];
+	const char *txt;
 
-	if( skip_white_space( streamib ) )
+	if( vips_streamib_skip_whitespace( streamib ) ||
+		!(txt = vips_streamib_get_non_whitespace( streamib )) )
 		return( -1 );
 
-	read_non_white_space( streamib, buf, MAX_THING );
-	*i = atoi( buf ); 
-
-	return( 0 );
-}
-
-static int
-read_float( VipsStreamib *streamib, float *f )
-{
-	char buf[MAX_THING];
-
-	if( skip_white_space( streamib ) )
-		return( -1 );
-
-	read_non_white_space( streamib, buf, MAX_THING );
 	/* We don't want the locale str -> float conversion.
 	 */
-	*f = g_ascii_strtod( buf, NULL );
+	*f = g_ascii_strtod( txt, NULL );
 
 	return( 0 );
 }
@@ -289,6 +217,9 @@ vips_foreign_load_ppm_parse_header( VipsForeignLoadPpm *ppm )
 		1, 1, 1, 0, 0, 0, 0, 0
 	};
 
+	if( vips_streami_rewind( ppm->streami ) )
+		return( -1 );
+
 	/* Read in the magic number.
 	 */
 	buf[0] = VIPS_STREAMIB_GETC( ppm->streamib );
@@ -312,8 +243,8 @@ vips_foreign_load_ppm_parse_header( VipsForeignLoadPpm *ppm )
 
 	/* Read in size.
 	 */
-	if( read_int( ppm->streamib, &ppm->width ) ||
-		read_int( ppm->streamib, &ppm->height ) )
+	if( get_int( ppm->streamib, &ppm->width ) ||
+		get_int( ppm->streamib, &ppm->height ) )
 		return( -1 );
 
 	/* Read in max value / scale for >1 bit images.
@@ -321,7 +252,7 @@ vips_foreign_load_ppm_parse_header( VipsForeignLoadPpm *ppm )
 	if( ppm->bits > 1 ) {
 		if( ppm->index == 6 || 
 			ppm->index == 7 ) {
-			if( read_float( ppm->streamib, &ppm->scale ) )
+			if( get_float( ppm->streamib, &ppm->scale ) )
 				return( -1 );
 
 			/* Scale > 0 means big-endian.
@@ -329,7 +260,7 @@ vips_foreign_load_ppm_parse_header( VipsForeignLoadPpm *ppm )
 			ppm->msb_first = ppm->scale > 0;
 		}
 		else {
-			if( read_int( ppm->streamib, &ppm->max_value ) )
+			if( get_int( ppm->streamib, &ppm->max_value ) )
 				return( -1 );
 
 			if( ppm->max_value > 255 )
@@ -445,6 +376,8 @@ vips_foreign_load_ppm_header( VipsForeignLoad *load )
 
 	vips_foreign_load_ppm_set_image( ppm, load->out );
 
+	vips_streami_minimise( ppm->streami );
+
 	return( 0 );
 }
 
@@ -499,7 +432,7 @@ load_1bit_ascii( VipsForeignLoadPpm *ppm, VipsImage *image )
 		for( x = 0; x < image->Xsize; x++ ) {
 			int val;
 
-			if( read_int( ppm->streamib, &val ) )
+			if( get_int( ppm->streamib, &val ) )
 				return( -1 );
 
 			if( val )
@@ -567,7 +500,7 @@ load_ascii( VipsForeignLoadPpm *ppm, VipsImage *image )
 		for( x = 0; x < image->Xsize * image->Bands; x++ ) {
 			int val;
 
-			if( read_int( ppm->streamib, &val ) )
+			if( get_int( ppm->streamib, &val ) )
 				return( -1 );
 			
 			switch( image->BandFmt ) {
@@ -620,9 +553,12 @@ vips_foreign_load_ppm_load( VipsForeignLoad *load )
 	else 
 		loader = load_ascii;
 
-	if( loader( ppm, load->real ) )
+	if( vips_streami_decode( ppm->streami ) ||
+		loader( ppm, load->real ) )
 		return( -1 );
 
+	vips_streami_minimise( ppm->streami );
+
 	return( 0 );
 }
 
diff --git a/libvips/foreign/ppmsave.c b/libvips/foreign/ppmsave.c
index 3b986d0f..0ea64f0b 100644
--- a/libvips/foreign/ppmsave.c
+++ b/libvips/foreign/ppmsave.c
@@ -46,44 +46,292 @@
 #include <string.h>
 
 #include <vips/vips.h>
+#include <vips/internal.h>
 
 #include "pforeign.h"
 
 #ifdef HAVE_PPM
 
+typedef struct _VipsForeignSavePpm VipsForeignSavePpm;
+
+typedef int (*VipsSavePpmFn)( VipsForeignSavePpm *, VipsImage *, VipsPel * );
+
 typedef struct _VipsForeignSavePpm {
 	VipsForeignSave parent_object;
 
-	char *filename; 
+	VipsStreamo *streamo;
 	gboolean ascii;
 	gboolean squash;
+
+	VipsSavePpmFn fn;
 } VipsForeignSavePpm;
 
 typedef VipsForeignSaveClass VipsForeignSavePpmClass;
 
-G_DEFINE_TYPE( VipsForeignSavePpm, vips_foreign_save_ppm, 
+G_DEFINE_ABSTRACT_TYPE( VipsForeignSavePpm, vips_foreign_save_ppm, 
 	VIPS_TYPE_FOREIGN_SAVE );
 
+static void
+vips_foreign_save_ppm_dispose( GObject *gobject )
+{
+	VipsForeignSavePpm *ppm = (VipsForeignSavePpm *) gobject;
+
+	if( ppm->streamo ) 
+		vips_streamo_finish( ppm->streamo );
+	VIPS_UNREF( ppm->streamo );
+
+	G_OBJECT_CLASS( vips_foreign_save_ppm_parent_class )->
+		dispose( gobject );
+}
+
+static int
+vips_foreign_save_ppm_line_ascii( VipsForeignSavePpm *ppm, 
+        VipsImage *image, VipsPel *p )
+{
+	const int n_elements = image->Xsize * image->Bands;
+
+	int i;
+
+	for( i = 0; i < n_elements; i++ ) {
+		switch( image->BandFmt ) {
+		case VIPS_FORMAT_UCHAR:
+			vips_streamo_writef( ppm->streamo, 
+				"%d ", p[i] );
+			break;
+
+		case VIPS_FORMAT_USHORT:
+			vips_streamo_writef( ppm->streamo, 
+				"%d ", ((unsigned short *) p)[i] );
+			break;
+
+		case VIPS_FORMAT_UINT:
+			vips_streamo_writef( ppm->streamo, 
+				"%d ", ((unsigned int *) p)[i] );
+			break;
+
+		default:
+			g_assert_not_reached();
+		}
+	}
+
+	if( vips_streamo_writes( ppm->streamo, "\n" ) ) 
+		return( -1 );
+
+	return( 0 );
+}
+
+static int
+vips_foreign_save_ppm_line_ascii_squash( VipsForeignSavePpm *ppm, 
+        VipsImage *image, VipsPel *p )
+{
+	int x;
+
+	for( x = 0; x < image->Xsize; x++ ) 
+		vips_streamo_writef( ppm->streamo, "%d ", p[x] ? 0 : 1 );
+
+	if( vips_streamo_writes( ppm->streamo, "\n" ) ) 
+		return( -1 );
+
+	return( 0 );
+}
+
+static int
+vips_foreign_save_ppm_line_binary( VipsForeignSavePpm *ppm, 
+        VipsImage *image, VipsPel *p )
+{
+	if( vips_streamo_write( ppm->streamo, 
+		p, VIPS_IMAGE_SIZEOF_LINE( image ) ) ) 
+		return( -1 );
+
+	return( 0 );
+}
+
+static int
+vips_foreign_save_ppm_line_binary_squash( VipsForeignSavePpm *ppm, 
+	VipsImage *image, VipsPel *p )
+{
+	int x;
+	int bits;
+	int n_bits;
+
+	bits = 0;
+	n_bits = 0;
+	for( x = 0; x < image->Xsize; x++ ) {
+		bits = VIPS_LSHIFT_INT( bits, 1 );
+		n_bits += 1;
+		bits |= p[x] ? 0 : 1;
+
+		if( n_bits == 8 ) {
+			if( VIPS_STREAMO_PUTC( ppm->streamo, bits ) ) 
+				return( -1 );
+
+			bits = 0;
+			n_bits = 0;
+		}
+	}
+
+	/* Flush any remaining bits in this line.
+	 */
+	if( n_bits &&
+		VIPS_STREAMO_PUTC( ppm->streamo, bits ) ) 
+		return( -1 );
+
+	return( 0 );
+}
+
+static int
+vips_foreign_save_ppm_block( VipsRegion *region, VipsRect *area, void *a )
+{
+	VipsForeignSavePpm *ppm = (VipsForeignSavePpm *) a;
+	VipsImage *image = region->im;
+	int i;
+
+	for( i = 0; i < area->height; i++ ) {
+		VipsPel *p = VIPS_REGION_ADDR( region, 0, area->top + i );
+
+		if( ppm->fn( ppm, image, p ) )
+			return( -1 );
+	}
+
+	return( 0 );
+}
+
+static int
+vips_foreign_save_ppm( VipsForeignSavePpm *ppm, VipsImage *image )
+{
+	char *magic;
+	char *date;
+
+	magic = "unset";
+	if( image->BandFmt == VIPS_FORMAT_FLOAT && 
+		image->Bands == 3 ) 
+		magic = "PF";
+	else if( image->BandFmt == VIPS_FORMAT_FLOAT && 
+		image->Bands == 1 ) 
+		magic = "Pf";
+	else if( image->Bands == 1 && 
+		ppm->ascii && 
+		ppm->squash )
+		magic = "P1";
+	else if( image->Bands == 1 && 
+		ppm->ascii )
+		magic = "P2";
+	else if( image->Bands == 1 && 
+		!ppm->ascii && 
+		ppm->squash )
+		magic = "P4";
+	else if( image->Bands == 1 && 
+		!ppm->ascii )
+		magic = "P5";
+	else if( image->Bands == 3 && 
+		ppm->ascii )
+		magic = "P3";
+	else if( image->Bands == 3 && 
+		!ppm->ascii )
+		magic = "P6";
+	else
+		g_assert_not_reached();
+
+	vips_streamo_writef( ppm->streamo, "%s\n", magic );
+	date = vips__get_iso8601();
+	vips_streamo_writef( ppm->streamo, 
+		"#vips2ppm - %s\n", date );
+	g_free( date );
+	vips_streamo_writef( ppm->streamo, 
+		"%d %d\n", image->Xsize, image->Ysize );
+
+	if( !ppm->squash ) 
+		switch( image->BandFmt ) {
+		case VIPS_FORMAT_UCHAR:
+			vips_streamo_writef( ppm->streamo, 
+				"%d\n", UCHAR_MAX );
+			break;
+
+		case VIPS_FORMAT_USHORT:
+			vips_streamo_writef( ppm->streamo, 
+				"%d\n", USHRT_MAX );
+			break;
+
+		case VIPS_FORMAT_UINT:
+			vips_streamo_writef( ppm->streamo, 
+				"%d\n", UINT_MAX );
+			break;
+
+		case VIPS_FORMAT_FLOAT:
+{
+			double scale;
+			char buf[G_ASCII_DTOSTR_BUF_SIZE];
+
+			if( vips_image_get_double( image, 
+				"pfm-scale", &scale ) )
+				scale = 1;
+			if( !vips_amiMSBfirst() )
+				scale *= -1;
+			/* Need to be locale independent.
+			 */
+			g_ascii_dtostr( buf, G_ASCII_DTOSTR_BUF_SIZE, scale );
+			vips_streamo_writes( ppm->streamo, buf );
+}
+			break;
+
+		default:
+			g_assert_not_reached();
+		}
+
+	if( ppm->squash )
+		ppm->fn = ppm->ascii ? 
+			vips_foreign_save_ppm_line_ascii_squash : 
+			vips_foreign_save_ppm_line_binary_squash;
+	else
+		ppm->fn = ppm->ascii ? 
+			vips_foreign_save_ppm_line_ascii : 
+			vips_foreign_save_ppm_line_binary;
+
+	if( vips_sink_disc( image, vips_foreign_save_ppm_block, ppm ) )
+		return( -1 );
+
+	return( 0 );
+}
+
 static int
 vips_foreign_save_ppm_build( VipsObject *object )
 {
 	VipsForeignSave *save = (VipsForeignSave *) object;
 	VipsForeignSavePpm *ppm = (VipsForeignSavePpm *) object;
 
-	VipsStreamo *streamo;
+	VipsImage *image;
 
 	if( VIPS_OBJECT_CLASS( vips_foreign_save_ppm_parent_class )->
 		build( object ) )
 		return( -1 );
 
-	if( !(streamo = vips_streamo_new_to_filename( ppm->filename )) )
-		return( -1 );
-	if( vips__ppm_save_stream( save->ready, streamo, 
-		ppm->ascii, ppm->squash ) ) {
-		VIPS_UNREF( streamo );
+	image = save->ready;
+	if( vips_check_uintorf( "vips2ppm", image ) || 
+		vips_check_bands_1or3( "vips2ppm", image ) || 
+		vips_check_uncoded( "vips2ppm", image ) || 
+		vips_image_pio_input( image ) )
 		return( -1 );
+
+	if( ppm->ascii && 
+		image->BandFmt == VIPS_FORMAT_FLOAT ) {
+		g_warning( "%s", 
+			_( "float images must be binary -- disabling ascii" ) );
+		ppm->ascii = FALSE;
 	}
-	VIPS_UNREF( streamo );
+
+	/* One bit images must come from a 8 bit, one band source. 
+	 */
+	if( ppm->squash && 
+		(image->Bands != 1 || 
+		 image->BandFmt != VIPS_FORMAT_UCHAR) ) {
+		g_warning( "%s", 
+			_( "can only squash 1 band uchar images -- " 
+				"disabling squash" ) );
+		ppm->squash = FALSE; 
+	}
+
+	if( vips_foreign_save_ppm( ppm, image ) )
+		return( -1 );
 
 	return( 0 );
 }
@@ -114,11 +362,12 @@ vips_foreign_save_ppm_class_init( VipsForeignSavePpmClass *class )
 	VipsForeignClass *foreign_class = (VipsForeignClass *) class;
 	VipsForeignSaveClass *save_class = (VipsForeignSaveClass *) class;
 
+	gobject_class->dispose = vips_foreign_save_ppm_dispose;
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
 
-	object_class->nickname = "ppmsave";
-	object_class->description = _( "save image to ppm file" );
+	object_class->nickname = "ppmsave_base";
+	object_class->description = _( "save to ppm" );
 	object_class->build = vips_foreign_save_ppm_build;
 
 	foreign_class->suffs = vips__ppm_suffs;
@@ -126,13 +375,6 @@ vips_foreign_save_ppm_class_init( VipsForeignSavePpmClass *class )
 	save_class->saveable = VIPS_SAVEABLE_RGB;
 	save_class->format_table = bandfmt_ppm;
 
-	VIPS_ARG_STRING( class, "filename", 1, 
-		_( "Filename" ),
-		_( "Filename to save to" ),
-		VIPS_ARGUMENT_REQUIRED_INPUT, 
-		G_STRUCT_OFFSET( VipsForeignSavePpm, filename ),
-		NULL );
-
 	VIPS_ARG_BOOL( class, "ascii", 10, 
 		_( "ASCII" ), 
 		_( "save as ascii" ),
@@ -146,6 +388,7 @@ vips_foreign_save_ppm_class_init( VipsForeignSavePpmClass *class )
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsForeignSavePpm, squash ),
 		FALSE );
+
 }
 
 static void
@@ -153,6 +396,60 @@ vips_foreign_save_ppm_init( VipsForeignSavePpm *ppm )
 {
 }
 
+typedef struct _VipsForeignSavePpmFile {
+	VipsForeignSavePpm parent_object;
+
+	char *filename; 
+} VipsForeignSavePpmFile;
+
+typedef VipsForeignSavePpmClass VipsForeignSavePpmFileClass;
+
+G_DEFINE_TYPE( VipsForeignSavePpmFile, vips_foreign_save_ppm_file, 
+	vips_foreign_save_ppm_get_type() );
+
+static int
+vips_foreign_save_ppm_file_build( VipsObject *object )
+{
+	VipsForeignSavePpm *ppm = (VipsForeignSavePpm *) object;
+	VipsForeignSavePpmFile *file = (VipsForeignSavePpmFile *) object;
+
+	if( file->filename &&
+		!(ppm->streamo = 
+			vips_streamo_new_to_filename( file->filename )) )
+		return( -1 );
+
+	return( VIPS_OBJECT_CLASS( vips_foreign_save_ppm_file_parent_class )->
+		build( object ) );
+}
+
+static void
+vips_foreign_save_ppm_file_class_init( VipsForeignSavePpmFileClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *object_class = (VipsObjectClass *) class;
+
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	object_class->nickname = "ppmsave";
+	object_class->description = _( "save image to ppm file" );
+	object_class->build = vips_foreign_save_ppm_file_build;
+
+	VIPS_ARG_STRING( class, "filename", 1, 
+		_( "Filename" ),
+		_( "Filename to save to" ),
+		VIPS_ARGUMENT_REQUIRED_INPUT, 
+		G_STRUCT_OFFSET( VipsForeignSavePpmFile, filename ),
+		NULL );
+
+}
+
+static void
+vips_foreign_save_ppm_file_init( VipsForeignSavePpmFile *file )
+{
+}
+
+
 #endif /*HAVE_PPM*/
 
 /**
diff --git a/libvips/foreign/radiance.c b/libvips/foreign/radiance.c
index c6bcca02..360045d5 100644
--- a/libvips/foreign/radiance.c
+++ b/libvips/foreign/radiance.c
@@ -506,11 +506,11 @@ getheader(		/* get header from file */
 )
 {
 	for(;;) { 
-		const unsigned char *line;
+		const char *line;
 
 		if( !(line = vips_streamib_get_line( streamib )) )
 			return( -1 );
-		if( strcmp( (char *) line, "" ) == 0 )
+		if( strcmp( line, "" ) == 0 )
 			/* Blank line. We've parsed the header successfully.
 			 */
 			break;
@@ -725,14 +725,14 @@ int
 vips__rad_israd( VipsStreami *streami )
 {
 	VipsStreamib *streamib;
-	const unsigned char *line;
+	const char *line;
 	int result;
 
 	/* Just test that the first line is the magic string.
 	 */
 	streamib = vips_streamib_new( streami );
 	result = (line = vips_streamib_get_line( streamib )) &&
-		strcmp( (char *) line, "#?RADIANCE" ) == 0;
+		strcmp( line, "#?RADIANCE" ) == 0;
 	VIPS_UNREF( streamib );
 
 	return( result );
@@ -832,7 +832,7 @@ static int
 rad2vips_get_header( Read *read, VipsImage *out )
 {
 	VipsInterpretation interpretation;
-	const unsigned char *line;
+	const char *line;
 	int width;
 	int height;
 	int i, j;
@@ -1082,7 +1082,7 @@ vips2rad_put_header( Write *write )
 {
 	vips2rad_make_header( write );
 
-	vips_streamo_writef( write->streamo, "#?RADIANCE\n" );
+	vips_streamo_writes( write->streamo, "#?RADIANCE\n" );
 	vips_streamo_writef( write->streamo, "%s%s\n", FMTSTR, write->format );
 	vips_streamo_writef( write->streamo, "%s%e\n", EXPOSSTR, write->expos );
 	vips_streamo_writef( write->streamo, 
@@ -1099,9 +1099,9 @@ vips2rad_put_header( Write *write )
 		write->prims[GRN][CIEX], write->prims[GRN][CIEY], 
 		write->prims[BLU][CIEX], write->prims[BLU][CIEY], 
 		write->prims[WHT][CIEX], write->prims[WHT][CIEY] );
-	vips_streamo_writef( write->streamo, "\n" );
-	vips_streamo_writef( write->streamo, 
-		"%s", resolu2str( resolu_buf, &write->rs ) );
+	vips_streamo_writes( write->streamo, "\n" );
+	vips_streamo_writes( write->streamo, 
+		resolu2str( resolu_buf, &write->rs ) );
 
 	return( 0 );
 }
diff --git a/libvips/include/vips/stream.h b/libvips/include/vips/stream.h
index 34ed9b5b..533f13c6 100644
--- a/libvips/include/vips/stream.h
+++ b/libvips/include/vips/stream.h
@@ -297,8 +297,10 @@ int vips_streamib_require( VipsStreamib *streamib, int require );
 #define VIPS_STREAMIB_PEEK( S ) ((S)->input_buffer + (S)->read_point)
 #define VIPS_STREAMIB_FETCH( S ) ((S)->input_buffer[(S)->read_point++])
 
-const unsigned char *vips_streamib_get_line( VipsStreamib *streamib ); 
-unsigned char *vips_streamib_get_line_copy( VipsStreamib *streamib ); 
+const char *vips_streamib_get_line( VipsStreamib *streamib ); 
+char *vips_streamib_get_line_copy( VipsStreamib *streamib ); 
+const char *vips_streamib_get_non_whitespace( VipsStreamib *streamib );
+int vips_streamib_skip_whitespace( VipsStreamib *streamib );
 
 #define VIPS_TYPE_STREAMIW (vips_streamiw_get_type())
 #define VIPS_STREAMIW( obj ) \
@@ -400,13 +402,12 @@ int vips_streamo_write( VipsStreamo *streamo, const void *data, size_t length );
 void vips_streamo_finish( VipsStreamo *streamo );
 
 int vips_streamo_putc( VipsStreamo *streamo, int ch );
-
 #define VIPS_STREAMO_PUTC( S, C ) ( \
 	(S)->write_point <= VIPS_STREAMO_BUFFER_SIZE ? \
 	((S)->output_buffer[(S)->write_point++] = (C), 0) : \
 	vips_streamo_putc( (S), (C) ) \
 )
-
+int vips_streamo_writes( VipsStreamo *streamo, const char *str );
 int vips_streamo_writef( VipsStreamo *streamo, const char *fmt, ... )
 	__attribute__((format(printf, 2, 3)));
 
diff --git a/libvips/include/vips/util.h b/libvips/include/vips/util.h
index dfe18ac9..61e09837 100644
--- a/libvips/include/vips/util.h
+++ b/libvips/include/vips/util.h
@@ -344,6 +344,8 @@ guint32 vips__random_add( guint32 seed, int value );
 const char *vips__icc_dir( void );
 const char *vips__windows_prefix( void );
 
+char *vips__get_iso8601( void );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/
diff --git a/libvips/iofuncs/streamib.c b/libvips/iofuncs/streamib.c
index bc4730a4..24319ce9 100644
--- a/libvips/iofuncs/streamib.c
+++ b/libvips/iofuncs/streamib.c
@@ -47,6 +47,7 @@
 #include <vips/intl.h>
 
 #include <stdio.h>
+#include <ctype.h>
 #include <stdlib.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -326,11 +327,11 @@ vips_streamib_require( VipsStreamib *streamib, int require )
  * slower vips_streamib_get_line_copy().
  *
  * The return value is owned by @streamib and must not be freed. It 
- * is valid until the next call to vips_streamib_get_line().
+ * is valid until the next get call @streamib.
  *
- * Returns: the next line from the file, or NULL on EOF or read error.
+ * Returns: the next line of text, or NULL on EOF or read error.
  */
-const unsigned char *
+const char *
 vips_streamib_get_line( VipsStreamib *streamib )
 {
 	int write_point;
@@ -379,7 +380,7 @@ vips_streamib_get_line( VipsStreamib *streamib )
 
 	VIPS_DEBUG_MSG( "    %s\n", streamib->line );
 
-	return( streamib->line );
+	return( (const char *) streamib->line );
 }
 
 /**
@@ -395,9 +396,9 @@ vips_streamib_get_line( VipsStreamib *streamib )
  * This is slower than vips_streamib_get_line(), but can work with lines of
  * any length.
  *
- * Returns: the next line from the file, or NULL on EOF or read error.
+ * Returns: the next line of text, or NULL on EOF or read error.
  */
-unsigned char *
+char *
 vips_streamib_get_line_copy( VipsStreamib *streamib )
 {
 	static const unsigned char null = '\0';
@@ -406,7 +407,7 @@ vips_streamib_get_line_copy( VipsStreamib *streamib )
 
 	GByteArray *buffer;
 	int ch;
-	unsigned char *result;
+	char *result;
 
 	buffer = g_byte_array_new();
 
@@ -435,9 +436,87 @@ vips_streamib_get_line_copy( VipsStreamib *streamib )
 
 	g_byte_array_append( buffer, &null, 1 );
 
-	result = (unsigned char *) g_byte_array_free( buffer, FALSE );
+	result = (char *) g_byte_array_free( buffer, FALSE );
 
 	VIPS_DEBUG_MSG( "    %s\n", result );
 
 	return( result );
 }
+
+/**
+ * vips_streamib_get_non_whitespace:
+ * @streamib: stream to operate on
+ *
+ * Fetch the next chunk of non-whitespace text from the stream, and
+ * null-terminate it. 
+ *
+ * After this, the next getc will be the first char of the next block of
+ * whitespace (or EOF). 
+ *
+ * If the first getc is whitespace, stop instantly and return the empty
+ * string.
+ *
+ * If the item is longer than some arbitrary (but large) limit, it is
+ * truncated. 
+ *
+ * The return value is owned by @streamib and must not be freed. It 
+ * is valid until the next get call @streamib.
+ *
+ * Returns: the next block of non-whitespace, or NULL on EOF or read error.
+ */
+const char *
+vips_streamib_get_non_whitespace( VipsStreamib *streamib )
+{
+	int ch;
+	int i;
+
+	for( i = 0; i < VIPS_STREAMIB_BUFFER_SIZE &&
+		!isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) &&
+		ch != EOF; i++ ) 
+		streamib->line[i] = ch;
+	streamib->line[i] = '\0';
+
+	/* If we stopped before seeing any whitespace, skip to the end of the
+	 * block of non-whitespace.
+	 */
+	if( !isspace( ch ) ) 
+		while( !isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) &&
+			ch != EOF )
+			;
+
+	/* If we finally stopped on whitespace, step back one so the next get
+	 * will be whitespace (or EOF).
+	 */
+	if( isspace( ch ) ) 
+		VIPS_STREAMIB_UNGETC( streamib );
+
+	return( (const char *) streamib->line );
+}
+
+/**
+ * vips_streamib_skip_whitespace:
+ * @streamib: stream to operate on
+ *
+ * After this, the next getc will be the first char of the next block of
+ * non-whitespace (or EOF).
+ *
+ * Returns: 0 on success, -1 on error.
+ */
+int 
+vips_streamib_skip_whitespace( VipsStreamib *streamib )
+{
+        int ch;
+
+	while( isspace( ch = VIPS_STREAMIB_GETC( streamib ) ) )
+		;
+	VIPS_STREAMIB_UNGETC( streamib );
+
+	/* # skip comments too.
+	 */
+	if( ch == '#' &&
+		(!vips_streamib_get_line( streamib ) ||
+		 vips_streamib_skip_whitespace( streamib )) )
+		return( -1 );
+
+	return( 0 );
+}
diff --git a/libvips/iofuncs/streamo.c b/libvips/iofuncs/streamo.c
index 7c0d62dd..57ca95c3 100644
--- a/libvips/iofuncs/streamo.c
+++ b/libvips/iofuncs/streamo.c
@@ -402,35 +402,6 @@ vips_streamo_finish( VipsStreamo *streamo )
 		class->finish( streamo );
 }
 
-/**
- * vips_streamo_writef:
- * @streamo: output stream to operate on
- * @fmt: <function>printf()</function>-style format string
- * @...: arguments to format string
- *
- * Format the string and write to @streamo. 
- * 
- * Returns: 0 on success, and -1 on error.
- */
-int
-vips_streamo_writef( VipsStreamo *streamo, const char *fmt, ... )
-{
-	va_list ap;
-	char *line;
-	int result;
-
-        va_start( ap, fmt );
-	line = g_strdup_vprintf( fmt, ap ); 
-        va_end( ap );
-
-	result = vips_streamo_write( streamo, 
-		(unsigned char *) line, strlen( line ) );
-
-	g_free( line ); 
-
-	return( result ); 
-}
-
 /**
  * vips_streamo_putc:
  * @streamo: output stream to operate on
@@ -455,6 +426,50 @@ vips_streamo_putc( VipsStreamo *streamo, int ch )
 	return( 0 );
 }
 
+/**
+ * vips_streamo_writes:
+ * @streamo: output stream to operate on
+ * @str: string to write
+ *
+ * Write a null-terminated string to @streamo.
+ * 
+ * Returns: 0 on success, and -1 on error.
+ */
+int
+vips_streamo_writes( VipsStreamo *streamo, const char *str )
+{
+	return( vips_streamo_write( streamo, 
+		(unsigned char *) str, strlen( str ) ) );
+}
+
+/**
+ * vips_streamo_writef:
+ * @streamo: output stream to operate on
+ * @fmt: <function>printf()</function>-style format string
+ * @...: arguments to format string
+ *
+ * Format the string and write to @streamo. 
+ * 
+ * Returns: 0 on success, and -1 on error.
+ */
+int
+vips_streamo_writef( VipsStreamo *streamo, const char *fmt, ... )
+{
+	va_list ap;
+	char *line;
+	int result;
+
+        va_start( ap, fmt );
+	line = g_strdup_vprintf( fmt, ap ); 
+        va_end( ap );
+
+	result = vips_streamo_writes( streamo, line ); 
+
+	g_free( line ); 
+
+	return( result ); 
+}
+
 /**
  * vips_streamo_write_amp: 
  * @streamo: output stream to operate on
diff --git a/libvips/iofuncs/util.c b/libvips/iofuncs/util.c
index b334a972..80d11403 100644
--- a/libvips/iofuncs/util.c
+++ b/libvips/iofuncs/util.c
@@ -2024,3 +2024,28 @@ vips__windows_prefix( void )
 	return( (const char *) g_once( &once, 
 		(GThreadFunc) vips__windows_prefix_once, NULL ) );
 }
+
+char *
+vips__get_iso8601( void )
+{
+	char *date;
+
+#ifdef HAVE_DATE_TIME_FORMAT_ISO8601
+{
+	GDateTime *now;
+
+	now = g_date_time_new_now_local();
+	date = g_date_time_format_iso8601( now );
+	g_date_time_unref( now );
+}
+#else /*!HAVE_DATE_TIME_FORMAT_ISO8601*/
+{
+	GTimeVal now;
+
+	g_get_current_time( &now );
+	date = g_time_val_to_iso8601( &now ); 
+}
+#endif /*HAVE_DATE_TIME_FORMAT_ISO8601*/
+
+	return( date );
+}
diff --git a/libvips/iofuncs/vips.c b/libvips/iofuncs/vips.c
index 26d43687..b7f40c10 100644
--- a/libvips/iofuncs/vips.c
+++ b/libvips/iofuncs/vips.c
@@ -957,22 +957,7 @@ vips__xml_properties( VipsImage *image )
 	VipsDbuf dbuf;
 	char *date;
 
-#ifdef HAVE_DATE_TIME_FORMAT_ISO8601
-{
-	GDateTime *now;
-
-	now = g_date_time_new_now_local();
-	date = g_date_time_format_iso8601( now );
-	g_date_time_unref( now );
-}
-#else /*!HAVE_DATE_TIME_FORMAT_ISO8601*/
-{
-	GTimeVal now;
-
-	g_get_current_time( &now );
-	date = g_time_val_to_iso8601( &now ); 
-}
-#endif /*HAVE_DATE_TIME_FORMAT_ISO8601*/
+	date = vips__get_iso8601();
 
 	vips_dbuf_init( &dbuf ); 
 	vips_dbuf_writef( &dbuf, "<?xml version=\"1.0\"?>\n" );