diff --git a/libvips/conversion/cast.c b/libvips/conversion/cast.c
index f9197478..3e4bb0fb 100644
--- a/libvips/conversion/cast.c
+++ b/libvips/conversion/cast.c
@@ -587,7 +587,7 @@ vips_castv( VipsImage *in, VipsImage **out, VipsBandFormat format, va_list ap )
  *
  * Optional arguments:
  *
- * * @shift: integer values are shifted
+ * * @shift: %gboolean, integer values are shifted
  *
  * Convert @in to @format. You can convert between any pair of formats.
  * Floats are truncated (not rounded). Out of range values are clipped.
diff --git a/libvips/conversion/msb.c b/libvips/conversion/msb.c
index 9aeae360..34858166 100644
--- a/libvips/conversion/msb.c
+++ b/libvips/conversion/msb.c
@@ -269,7 +269,7 @@ vips_msb_init( VipsMsb *msb )
  *
  * Optional arguments:
  *
- * * @band: msb just this band
+ * * @band: %gint, msb just this band
  *
  * Turn any integer image to 8-bit unsigned char by discarding all but the most
  * significant byte. Signed values are converted to unsigned by adding 128.