diff --git a/ChangeLog b/ChangeLog
index b859537f..37706daa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,7 @@
 13/3/12 started 7.28.2
 - better PNG alpha handling
 - sanity-check PNG read geometry
+- xres/yres tiffsave args were broken
 
 13/3/12 started 7.28.1
 - add ICC profile read/write for png files
diff --git a/libvips/foreign/tiff2vips.c b/libvips/foreign/tiff2vips.c
index 212d16c5..74b21428 100644
--- a/libvips/foreign/tiff2vips.c
+++ b/libvips/foreign/tiff2vips.c
@@ -884,7 +884,7 @@ parse_resolution( TIFF *tiff, VipsImage *out )
 	return( 0 );
 }
 
-/* Look at PhotometricInterpretation and BitsPerPixel, and try to figure out 
+/* Look at PhotometricInterpretation and BitsPerPixel and try to figure out 
  * which of the image classes this is.
  */
 static int
@@ -1143,7 +1143,7 @@ tiff_fill_region_aligned( VipsRegion *out, void *seq, void *a, void *b )
 	return( 0 );
 }
 
-/* Loop over the output region, painting in tiles from the file.
+/* Loop over the output region painting in tiles from the file.
  */
 static int
 tiff_fill_region( VipsRegion *out, void *seq, void *a, void *b, gboolean *stop )
@@ -1163,7 +1163,7 @@ tiff_fill_region( VipsRegion *out, void *seq, void *a, void *b, gboolean *stop )
 
 	/* Sizeof a pel in the TIFF file. This won't work for formats which
 	 * are <1 byte per pel, like onebit :-( Fortunately, it's only used
-	 * to calculate addresses within a tile, and because we are wrapped in
+	 * to calculate addresses within a tile and, because we are wrapped in
 	 * vips_tilecache(), we will never have to calculate positions not 
 	 * within a tile.
 	 */
@@ -1172,7 +1172,7 @@ tiff_fill_region( VipsRegion *out, void *seq, void *a, void *b, gboolean *stop )
 	int x, y, z;
 
 	/* Special case: we are filling a single tile exactly sized to match
-	 * the tiff tile, and we have no repacking to do for this format.
+	 * the tiff tile and we have no repacking to do for this format.
 	 */
 	if( rtiff->memcpy &&
 		r->left % rtiff->twidth == 0 &&
@@ -1203,7 +1203,7 @@ tiff_fill_region( VipsRegion *out, void *seq, void *a, void *b, gboolean *stop )
 			 */
 			vips_rect_intersectrect( &tile, r, &hit );
 
-			/* Unpack to VIPS format. We can do this in parallel.
+			/* Unpack to VIPS format. 
 			 * Just unpack the section of the tile we need.
 			 */
 			for( z = 0; z < hit.height; z++ ) {
diff --git a/libvips/foreign/tiffsave.c b/libvips/foreign/tiffsave.c
index 6bccf9f1..2bb33b83 100644
--- a/libvips/foreign/tiffsave.c
+++ b/libvips/foreign/tiffsave.c
@@ -2,6 +2,8 @@
  *
  * 2/12/11
  * 	- wrap a class around the tiff writer
+ * 17/3/12
+ * 	- argh xres/yres macro was wrong
  */
 
 /*
@@ -248,15 +250,15 @@ vips_foreign_save_tiff_class_init( VipsForeignSaveTiffClass *class )
 	VIPS_ARG_DOUBLE( class, "xres", 16, 
 		_( "Xres" ), 
 		_( "Horizontal resolution in pixels/mm" ),
-		VIPS_ARGUMENT_NONE,
-		G_STRUCT_OFFSET( VipsImage, Xres ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsForeignSaveTiff, xres ),
 		-0.0, 1000000, 0 );
 
 	VIPS_ARG_DOUBLE( class, "yres", 17, 
 		_( "Yres" ), 
 		_( "Vertical resolution in pixels/mm" ),
-		VIPS_ARGUMENT_NONE,
-		G_STRUCT_OFFSET( VipsImage, Yres ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsForeignSaveTiff, yres ),
 		-0.0, 1000000, 0 );
 
 	VIPS_ARG_BOOL( class, "bigtiff", 18,