--- ray/src/util/rad.c	2019/02/26 23:31:11	2.126
+++ ray/src/util/rad.c	2021/01/21 21:36:28	2.128
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: rad.c,v 2.126 2019/02/26 23:31:11 greg Exp $";
+static const char	RCSid[] = "$Id: rad.c,v 2.128 2021/01/21 21:36:28 greg Exp $";
 #endif
 /*
  * Executive program for oconv, rpict and pfilt
@@ -790,8 +790,8 @@ ambval(void)				/* compute ambient value */
 {
 	if (vdef(EXPOSURE)) {
 		if (vval(EXPOSURE)[0] == '+' || vval(EXPOSURE)[0] == '-')
-			return(.5/pow(2.,vflt(EXPOSURE)));
-		return(.5/vflt(EXPOSURE));
+			return(.18/pow(2.,vflt(EXPOSURE)));
+		return(.18/vflt(EXPOSURE));
 	}
 	if (vlet(ZONE) == 'E')
 		return(10.);
@@ -834,8 +834,12 @@ renderopts(			/* set rendering options */
 		op = addarg(addarg(op, "-ap"), pmapf);
 		if (atoi(bw) > 0) op = addarg(op, bw);
 	}
-	if (vdef(RENDER))
+	if (vdef(RENDER)) {
 		op = addarg(op, vval(RENDER));
+		bw = strstr(vval(RENDER), "-aa ");
+		if (bw != NULL && atof(bw+4) <= FTINY)
+			overture = 0;
+	}
 	if (rvdevice != NULL) {
 		if (vdef(RVU)) {
 			if (vval(RVU)[0] != '-') {