--- ray/src/cv/mgf2rad.c	2014/01/25 18:02:06	2.30
+++ ray/src/cv/mgf2rad.c	2016/10/03 18:16:45	2.31
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: mgf2rad.c,v 2.30 2014/01/25 18:02:06 greg Exp $";
+static const char	RCSid[] = "$Id: mgf2rad.c,v 2.31 2016/10/03 18:16:45 greg Exp $";
 #endif
 /*
  * Convert MGF (Materials and Geometry Format) to Radiance
@@ -584,7 +584,8 @@ material(void)			/* get (and print) current material *
 		return(mname);
 	}
 					/* check for plastic */
-	if (c_cmaterial->rs < .1) {
+	if (c_cmaterial->rs < .08 && (c_cmaterial->rs < .1*c_cmaterial->rd ||
+					c_isgrey(&c_cmaterial->rs_c))) {
 		cvtcolor(radrgb, &c_cmaterial->rd_c,
 					c_cmaterial->rd/(1.-c_cmaterial->rs));
 		fprintf(matfp, "\nvoid plastic %s\n0\n0\n", mname);