diff --git a/julia.c b/julia.c
index 4dcf007..692b16d 100644
--- a/julia.c
+++ b/julia.c
@@ -134,7 +134,7 @@ julia_main(int argc, char *argv[])
 	int palette_size = 720,
 	    width = 640,
 	    height = 400,
-	    i, j;
+	    rescache_width, rescache_height, i, j;
 	int ch, do_light = 0;
 
 	while ((ch = getopt(argc, argv, OPTSTRING)) != -1)
@@ -191,7 +191,11 @@ julia_main(int argc, char *argv[])
 
 	palette = palette_gen(palette_size);
 
-	if ((rescache = malloc(sizeof(*rescache) * width * height)) == NULL)
+	rescache_width = width + (do_light ? 1 : 0);
+	rescache_height = height + (do_light ? 1 : 0);
+
+	if ((rescache = malloc(sizeof(*rescache) * rescache_width
+	    * rescache_height)) == NULL)
 		errx(1, "out of memory");
 
 	if (do_light) {
@@ -220,22 +224,22 @@ julia_main(int argc, char *argv[])
 	print_critical_points();
 
 	sec_w /= zoom; sec_h /= zoom;
-	for (i = 0; i < height; i++) {
+	for (i = 0; i < rescache_height; i++) {
 		zy = cen_y + (0.5L - i / (long double)height) * sec_h;
-		for (j = 0; j < width; j++) {
+		for (j = 0; j < rescache_width; j++) {
 			zx = cen_x + (j / (long double)width - 0.5L) * sec_w;
 			z = zx + I * zy;
 			it = iterate(z, julia, &rit);
-			rescache[i * width + j].it = it;
-			rescache[i * width + j].rit = rit;
+			rescache[i * rescache_width + j].it = it;
+			rescache[i * rescache_width + j].rit = rit;
 		}
 	}
 
-	pnmout_header(stdout, width - 1, height - 1);
-	for (i = 0; i < height - 1; i++) {
-		for (j = 0; j < width - 1; j++) {
-			it = rescache[i * width + j].it;
-			rit = rescache[i * width + j].rit;
+	pnmout_header(stdout, width, height);
+	for (i = 0; i < height; i++) {
+		for (j = 0; j < width; j++) {
+			it = rescache[i * rescache_width + j].it;
+			rit = rescache[i * rescache_width + j].rit;
 
 			if (it < 0)
 				color = contour_color;
@@ -243,10 +247,10 @@ julia_main(int argc, char *argv[])
 				ritnum = (it - rit) * density;
 				if (do_light) {
 					long double lxrn, lyrn, l, lx, ly, lz;
-					lxrn = rescache[i * width + j + 1].it
-					    - rescache[i * width + j + 1].rit;
-					lyrn = rescache[(i + 1) * width + j].it
-					    - rescache[(i + 1) * width + j].rit;
+					lxrn = rescache[i * rescache_width + j + 1].it
+					    - rescache[i * rescache_width + j + 1].rit;
+					lyrn = rescache[(i + 1) * rescache_width + j].it
+					    - rescache[(i + 1) * rescache_width + j].rit;
 					lx = -sec_h * (lxrn - it + rit);
 					ly = sec_w * (lyrn - it + rit);
 					lz = sec_w * sec_h;