diff --git a/ChangeLog b/ChangeLog
index 2f015aed..c1d3066f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,9 +9,13 @@
 - add vips_rotate() ... a convenience method for vips_similarity()
 - svgload was missing is_a [lovell]
 - better header sniffing for small files
+- drop incompatible ICC profiles before save
+- better hasalpha rules
+- create funcs always make MULTIBAND (ie. no alpha)
 
 12/3/18 started 8.6.4
 - better fitting of fonts with overhanging edges, thanks Adrià 
+- lower stack use in radsave to help musl [Jacob Thrane Lund]
 
 12/2/18 started 8.6.3
 - use pkg-config to find libjpeg, if we can
diff --git a/libvips/colour/icc_transform.c b/libvips/colour/icc_transform.c
index 7b9d0d53..67053214 100644
--- a/libvips/colour/icc_transform.c
+++ b/libvips/colour/icc_transform.c
@@ -1226,6 +1226,36 @@ vips_icc_ac2rc( VipsImage *in, VipsImage **out, const char *profile_filename )
 	return( 0 );
 }
 
+/* TRUE if a profile is compatible with an image.
+ */
+gboolean
+vips_icc_is_compatible_profile( VipsImage *image, 
+	void *data, size_t data_length )
+{
+	cmsHPROFILE profile;
+
+	if( !(profile = cmsOpenProfileFromMem( data, data_length )) ) {
+		g_warning( "%s", _( "corrupt profile" ) );
+		return( FALSE ); 
+	}
+
+	if( vips_image_expected_bands( image ) != 
+		vips_icc_profile_needs_bands( profile ) ) {
+		VIPS_FREEF( cmsCloseProfile, profile );
+		g_warning( "%s", 
+			_( "profile incompatible with image" ) );
+		return( FALSE );
+	}
+	if( vips_image_expected_sig( image ) != cmsGetColorSpace( profile ) ) {
+		VIPS_FREEF( cmsCloseProfile, profile );
+		g_warning( "%s", 
+			_( "profile colourspace differs from image" ) );
+		return( FALSE );
+	}
+
+	return( TRUE );
+}
+
 #else /*!HAVE_LCMS2*/
 
 #include <vips/vips.h>
@@ -1245,6 +1275,13 @@ vips_icc_ac2rc( VipsImage *in, VipsImage **out, const char *profile_filename )
 	return( -1 );
 }
 
+gboolean
+vips_icc_is_compatible_profile( VipsImage *image, 
+	void *data, size_t data_length )
+{
+	return( TRUE ); 
+}
+
 #endif /*HAVE_LCMS*/
 
 /**
diff --git a/libvips/conversion/bandjoin.c b/libvips/conversion/bandjoin.c
index f5327a48..7f284907 100644
--- a/libvips/conversion/bandjoin.c
+++ b/libvips/conversion/bandjoin.c
@@ -499,7 +499,7 @@ vips_bandjoin_const1( VipsImage *in, VipsImage **out, double c, ... )
 	return( result );
 }
 
-/* vips_addalpha:
+/* vips_addalpha: (method)
  * @in: input image
  * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
diff --git a/libvips/create/black.c b/libvips/create/black.c
index c613a154..33c4ab1c 100644
--- a/libvips/create/black.c
+++ b/libvips/create/black.c
@@ -15,6 +15,9 @@
  * 	- gtkdoc
  * 31/10/11
  * 	- redo as a class
+ * 3/4/18
+ * 	- always write MULTIBAND, otherwise when we join up these things it'll
+ * 	  look like we have an alpha
  */
 
 /*
@@ -97,8 +100,7 @@ vips_black_build( VipsObject *object )
 	vips_image_init_fields( create->out,
 		black->width, black->height, black->bands, 
 		VIPS_FORMAT_UCHAR, VIPS_CODING_NONE,
-                black->bands == 1 ? 
-			VIPS_INTERPRETATION_B_W : VIPS_INTERPRETATION_MULTIBAND,
+                VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 );
 	vips_image_pipelinev( create->out, 
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/create/gaussmat.c b/libvips/create/gaussmat.c
index fa67c305..4ac21562 100644
--- a/libvips/create/gaussmat.c
+++ b/libvips/create/gaussmat.c
@@ -134,7 +134,8 @@ vips_gaussmat_build( VipsObject *object )
 
 	vips_image_init_fields( create->out,
 		width, height, 1, 
-		VIPS_FORMAT_DOUBLE, VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
+		VIPS_FORMAT_DOUBLE, VIPS_CODING_NONE, 
+		VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 ); 
 	vips_image_pipelinev( create->out, 
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/create/gaussnoise.c b/libvips/create/gaussnoise.c
index 1566e39a..5ccf5510 100644
--- a/libvips/create/gaussnoise.c
+++ b/libvips/create/gaussnoise.c
@@ -134,7 +134,7 @@ vips_gaussnoise_build( VipsObject *object )
 	vips_image_init_fields( create->out,
 		gaussnoise->width, gaussnoise->height, 1,
 		VIPS_FORMAT_FLOAT, VIPS_CODING_NONE,
-		VIPS_INTERPRETATION_B_W, 1.0, 1.0 );
+		VIPS_INTERPRETATION_MULTIBAND, 1.0, 1.0 );
 	vips_image_pipelinev( create->out, 
 		VIPS_DEMAND_STYLE_ANY, NULL );
 
diff --git a/libvips/create/logmat.c b/libvips/create/logmat.c
index 5f15b3ea..43d753c7 100644
--- a/libvips/create/logmat.c
+++ b/libvips/create/logmat.c
@@ -153,7 +153,8 @@ vips_logmat_build( VipsObject *object )
 
 	vips_image_init_fields( create->out,
 		width, height, 1, 
-		VIPS_FORMAT_DOUBLE, VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
+		VIPS_FORMAT_DOUBLE, VIPS_CODING_NONE, 
+		VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 ); 
 	vips_image_pipelinev( create->out, 
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/create/perlin.c b/libvips/create/perlin.c
index 5181f365..a6651f90 100644
--- a/libvips/create/perlin.c
+++ b/libvips/create/perlin.c
@@ -249,7 +249,7 @@ vips_perlin_build( VipsObject *object )
 	vips_image_init_fields( create->out,
 		perlin->width, perlin->height, 1,
 		perlin->uchar ? VIPS_FORMAT_UCHAR : VIPS_FORMAT_FLOAT, 
-		VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
+		VIPS_CODING_NONE, VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 );
 	vips_image_pipelinev( create->out,
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/create/point.c b/libvips/create/point.c
index 06e14229..f5f00841 100644
--- a/libvips/create/point.c
+++ b/libvips/create/point.c
@@ -109,10 +109,9 @@ vips_point_build( VipsObject *object )
 			return( -1 );
 		in = t[2];
 
-		/* uchar mode always does B_W. We don't want FOURIER or
-		 * whatever in this case.
+		/* We don't want FOURIER or whatever in this case.
 		 */
-		in->Type = VIPS_INTERPRETATION_B_W;
+		in->Type = VIPS_INTERPRETATION_MULTIBAND;
 	}
 
 	if( vips_image_write( in, create->out ) )
@@ -137,7 +136,7 @@ vips_point_class_init( VipsPointClass *class )
 	class->point = NULL; 
 	class->min = -1.0; 
 	class->max = 1.0; 
-	class->interpretation = VIPS_INTERPRETATION_B_W;
+	class->interpretation = VIPS_INTERPRETATION_MULTIBAND;
 
 	VIPS_ARG_INT( class, "width", 2, 
 		_( "Width" ), 
diff --git a/libvips/create/text.c b/libvips/create/text.c
index 8d26ed10..e8631638 100644
--- a/libvips/create/text.c
+++ b/libvips/create/text.c
@@ -379,7 +379,8 @@ vips_text_build( VipsObject *object )
 
 	vips_image_init_fields( create->out,
 		text->bitmap.width, text->bitmap.rows, 1, 
-		VIPS_FORMAT_UCHAR, VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
+		VIPS_FORMAT_UCHAR, VIPS_CODING_NONE, 
+		VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 ); 
 	vips_image_pipelinev( create->out, 
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/create/worley.c b/libvips/create/worley.c
index 520fdd47..e2cdf424 100644
--- a/libvips/create/worley.c
+++ b/libvips/create/worley.c
@@ -281,7 +281,8 @@ vips_worley_build( VipsObject *object )
 
 	vips_image_init_fields( create->out,
 		worley->width, worley->height, 1,
-		VIPS_FORMAT_FLOAT, VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
+		VIPS_FORMAT_FLOAT, VIPS_CODING_NONE, 
+		VIPS_INTERPRETATION_MULTIBAND,
 		1.0, 1.0 );
 	vips_image_pipelinev( create->out,
 		VIPS_DEMAND_STYLE_ANY, NULL );
diff --git a/libvips/foreign/foreign.c b/libvips/foreign/foreign.c
index 61c87e03..f32302b9 100644
--- a/libvips/foreign/foreign.c
+++ b/libvips/foreign/foreign.c
@@ -22,6 +22,8 @@
  * 	- META_SEQ support moved here
  * 5/3/18
  * 	- block _start if one start fails, see #893
+ * 1/4/18
+ * 	- drop incompatible ICC profiles before save
  */
 
 /*
@@ -1504,6 +1506,21 @@ vips__foreign_convert_saveable( VipsImage *in, VipsImage **ready,
 		in = out;
 	}
 
+	/* Some format libraries, like libpng, will throw a hard error if the 
+	 * profile is inappropriate for this image type. With profiles inherited
+	 * from a source image, this can happen all the time, so we 
+	 * want to just drop the profile in this case.
+	 */
+	if( vips_image_get_typeof( in, VIPS_META_ICC_NAME ) ) {
+		void *data;
+		size_t length;
+
+		if( !vips_image_get_blob( in, VIPS_META_ICC_NAME, 
+			&data, &length ) &&
+			!vips_icc_is_compatible_profile( in, data, length ) ) 
+			vips_image_remove( in, VIPS_META_ICC_NAME );
+	}
+
 	*ready = in;
 
 	return( 0 );
diff --git a/libvips/foreign/radiance.c b/libvips/foreign/radiance.c
index 77906151..6903221b 100644
--- a/libvips/foreign/radiance.c
+++ b/libvips/foreign/radiance.c
@@ -19,6 +19,8 @@
  *	- add buffer save functions   
  * 28/2/17
  * 	- use dbuf for buffer output
+ * 4/4/17
+ * 	- reduce stack use to help musl
  */
 
 /*
@@ -885,10 +887,12 @@ rle_scanline_write( COLR *scanline, int width,
 	}
 }
 
-/* Write a single scanline.
+/* Write a single scanline. buffer is at least MAX_LINE bytes and is used to
+ * construct the RLE scanline. Don't allocate this on the stack so we don't
+ * die too horribly on small-stack libc.
  */
 static int
-scanline_write( COLR *scanline, int width, FILE *fp )
+scanline_write( unsigned char *buffer, COLR *scanline, int width, FILE *fp )
 {
 	if( width < MINELEN || 
 		width > MAXELEN )
@@ -898,11 +902,12 @@ scanline_write( COLR *scanline, int width, FILE *fp )
 	else {
 		/* An RLE scanline.
 		 */
-		unsigned char buffer[MAX_LINE];
 		int length;
 
 		rle_scanline_write( scanline, width, buffer, &length );
 
+		g_assert( length <= MAX_LINE ); 
+
 		return( fwrite( buffer, 1, length, fp ) - length );
 	}
 }
@@ -1290,12 +1295,23 @@ static int
 vips2rad_put_data_block( VipsRegion *region, VipsRect *area, void *a )
 {
 	Write *write = (Write *) a;
+
+	size_t size;
+	unsigned char *buffer;
 	int i;
 
+	/* You have to seek back after a write.
+	 */
+	buffer = vips_dbuf_get_write( &write->dbuf, &size );
+	vips_dbuf_seek( &write->dbuf, 0, SEEK_SET ); 
+
+	g_assert( size >= MAX_LINE ); 
+
 	for( i = 0; i < area->height; i++ ) {
 		VipsPel *p = VIPS_REGION_ADDR( region, 0, area->top + i );
 
-		if( scanline_write( (COLR *) p, area->width, write->fout ) ) 
+		if( scanline_write( buffer, 
+			(COLR *) p, area->width, write->fout ) ) 
 			return( -1 );
 	}
 
@@ -1329,6 +1345,11 @@ vips__rad_save( VipsImage *in, const char *filename )
 	write->filename = vips_strdup( NULL, filename );
 	write->fout = vips__file_open_write( filename, FALSE );
 
+	/* scanline_write() needs a buffer to write compressed scanlines to.
+	 * We use the dbuf ... why not.
+	 */
+	vips_dbuf_allocate( &write->dbuf, MAX_LINE );
+
 	if( !write->filename || 
 		!write->fout ||
 		vips2rad_put_header( write ) ||
diff --git a/libvips/foreign/vipspng.c b/libvips/foreign/vipspng.c
index b645da3a..a7aaf963 100644
--- a/libvips/foreign/vipspng.c
+++ b/libvips/foreign/vipspng.c
@@ -992,7 +992,8 @@ write_vips( Write *write,
 	/* If we're an intel byte order CPU and this is a 16bit image, we need
 	 * to swap bytes.
 	 */
-	if( bit_depth > 8 && !vips_amiMSBfirst() ) 
+	if( bit_depth > 8 && 
+		!vips_amiMSBfirst() ) 
 		png_set_swap( write->pPng ); 
 
 	if( interlace )	
diff --git a/libvips/include/vips/colour.h b/libvips/include/vips/colour.h
index 77404b9c..7978d325 100644
--- a/libvips/include/vips/colour.h
+++ b/libvips/include/vips/colour.h
@@ -177,6 +177,8 @@ int vips_icc_export( VipsImage *in, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_icc_ac2rc( VipsImage *in, VipsImage **out, 
 	const char *profile_filename );
+gboolean vips_icc_is_compatible_profile( VipsImage *image, 
+	void *data, size_t data_length );
 
 int vips_dE76( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 	__attribute__((sentinel));
diff --git a/libvips/iofuncs/image.c b/libvips/iofuncs/image.c
index 411e0b15..9045449f 100644
--- a/libvips/iofuncs/image.c
+++ b/libvips/iofuncs/image.c
@@ -12,8 +12,10 @@
  * 	- vips_image_write() does not ref input for non-partial images
  * 29/10/16
  * 	- add vips_image_hasalpha()
- * 11/10/1
+ * 11/10/17
  * 	- more severing for vips_image_write()
+ * 3/4/18
+ * 	- better rules for hasalpha
  */
 
 /*
@@ -2866,18 +2868,47 @@ vips_image_ispartial( VipsImage *image )
  * vips_image_hasalpha: (method)
  * @image: image to check
  *
- * libvips assumes an image has an alpha if it has two bands (ie. it is a
- * monochrome image with an extra band), if it has four bands (unless it's been
- * tagged as CMYK), or if it has more than four bands. 
+ * Look at an image's interpretation and see if it has extra alpha bands. For
+ * example, a 4-band #VIPS_INTERPRETATION_RGB would, but a six-band 
+ * #VIPS_INTERPRETATION_MULTIBAND would not. 
  *
  * Return %TRUE if @image has an alpha channel.
  */
 gboolean
 vips_image_hasalpha( VipsImage *image )
 {
-	return( image->Bands == 2 ||
-		(image->Bands == 4 && image->Type != VIPS_INTERPRETATION_CMYK) ||
-		image->Bands > 4 );
+	/* The result of hasalpha is used to turn on things like
+	 * premultiplication, so we are rather conservative about when we
+	 * signal this. We don't want to premultiply things that should not be
+	 * premultiplied.
+	 */
+	switch( image->Type ) { 
+	case VIPS_INTERPRETATION_B_W:
+	case VIPS_INTERPRETATION_GREY16:
+		return( image->Bands > 1 ); 
+
+	case VIPS_INTERPRETATION_RGB:
+	case VIPS_INTERPRETATION_CMC:
+	case VIPS_INTERPRETATION_LCH:
+	case VIPS_INTERPRETATION_LABS:
+	case VIPS_INTERPRETATION_sRGB:
+	case VIPS_INTERPRETATION_YXY:
+	case VIPS_INTERPRETATION_XYZ:
+	case VIPS_INTERPRETATION_LAB:
+	case VIPS_INTERPRETATION_RGB16:
+	case VIPS_INTERPRETATION_scRGB:
+	case VIPS_INTERPRETATION_HSV:
+		return( image->Bands > 3 ); 
+
+	case VIPS_INTERPRETATION_CMYK:
+		return( image->Bands > 4 ); 
+
+	default:
+		/* We can't really infer anything about bands from things like
+		 * HISTOGRAM or FOURIER.
+		 */
+		return( FALSE ); 
+	}
 }
 
 /**