diff --git a/libvips/colour/sRGB2HSV.c b/libvips/colour/sRGB2HSV.c
index 82afdb4f..b74704a5 100644
--- a/libvips/colour/sRGB2HSV.c
+++ b/libvips/colour/sRGB2HSV.c
@@ -100,7 +100,7 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 				q[0] = (unsigned char) ((secondary_diff / (float) delta) + wrap_around_hue);
 			}
 
-			q[1] = (unsigned char) ((float) delta / (float) c_max);
+			q[1] = (unsigned char) ((float) delta / (float) c_max)*256;
 		}
 
 		p += 3;