diff --git a/libvips/iofuncs/sinkmemory.c b/libvips/iofuncs/sinkmemory.c
index 8a49d475..82028348 100644
--- a/libvips/iofuncs/sinkmemory.c
+++ b/libvips/iofuncs/sinkmemory.c
@@ -31,8 +31,8 @@
  */
 
 /*
- */
 #define VIPS_DEBUG
+ */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
@@ -160,6 +160,9 @@ sink_progress( void *a )
 {
 	Sink *sink = (Sink *) a;
 
+	VIPS_DEBUG_MSG( "sink_progress: %d x %d\n",
+		sink->tile_width, sink->tile_height );
+
 	/* Trigger any eval callbacks on our source image and
 	 * check for errors.
 	 */
diff --git a/libvips/iofuncs/time.c b/libvips/iofuncs/time.c
index 9830b66e..fa3399e4 100644
--- a/libvips/iofuncs/time.c
+++ b/libvips/iofuncs/time.c
@@ -142,9 +142,12 @@ int
 im__handle_eval( IMAGE *im, int w, int h )
 {
 	if( im->progress ) {
-		/* Need to test ->time, it may have been shut down.
+		/* Need to test ->time, it may have been shut down. Also, only
+		 * bother updating the time struct if we have a callback that
+		 * might be interested.
 		 */
-		if( im->progress->time ) {
+		if( im->progress->time &&
+			im->progress->evalfns ) {
 			if( update_time( im->progress->time, w, h ) )
 				return( -1 );
 		}