diff --git a/src/dehacked.c b/src/dehacked.c
index 7107c3a1e..9a19833a9 100644
--- a/src/dehacked.c
+++ b/src/dehacked.c
@@ -808,9 +808,11 @@ static void readskincolor(MYFILE *f, INT32 num)
 			{
 				size_t namesize = sizeof(skincolors[num].name);
 				char truncword[namesize];
+				UINT16 dupecheck;
 
 				deh_strlcpy(truncword, word2, namesize, va("Skincolor %d: name", num)); // truncate here to check for dupes
-				if (truncword[0] != '\0' && (!stricmp(truncword, skincolors[SKINCOLOR_NONE].name) || R_GetColorByName(truncword)))
+				dupecheck = R_GetColorByName(truncword);
+				if (truncword[0] != '\0' && (!stricmp(truncword, skincolors[SKINCOLOR_NONE].name) || dupecheck && dupecheck != num))
 				{
 					size_t lastchar = strlen(truncword);
 					char oldword[lastchar+1];
@@ -4726,11 +4728,11 @@ static void DEH_LoadDehackedFile(MYFILE *f, boolean mainfile)
 				{
 					if (i == 0 && word2[0] != '0') // If word2 isn't a number
 						i = get_skincolor(word2); // find a skincolor by name
-					if (i < numskincolors && i >= (INT32)SKINCOLOR_FIRSTFREESLOT)
+					if (i && i < numskincolors)
 						readskincolor(f, i);
 					else
 					{
-						deh_warning("Skincolor %d out of range (%d - %d)", i, SKINCOLOR_FIRSTFREESLOT, numskincolors-1);
+						deh_warning("Skincolor %d out of range (1 - %d)", i, numskincolors-1);
 						ignorelines(f);
 					}
 				}
diff --git a/src/lua_infolib.c b/src/lua_infolib.c
index b3e92f833..830d97625 100644
--- a/src/lua_infolib.c
+++ b/src/lua_infolib.c
@@ -1491,7 +1491,7 @@ static void setRamp(lua_State *L, skincolor_t* c) {
 	UINT32 i;
 	lua_pushnil(L);
 	for (i=0; i<COLORRAMPSIZE; i++) {
-		if (lua_objlen(L,-2)<COLORRAMPSIZE) {
+		if (lua_objlen(L,-2)!=COLORRAMPSIZE) {
 			luaL_error(L, LUA_QL("skincolor_t") " field 'ramp' must be %d entries long; got %d.", COLORRAMPSIZE, lua_objlen(L,-2));
 			break;
 		}
@@ -1513,8 +1513,8 @@ static int lib_setSkinColor(lua_State *L)
 	lua_remove(L, 1); // don't care about skincolors[] userdata.
 	{
 		cnum = (UINT16)luaL_checkinteger(L, 1);
-		if (cnum < SKINCOLOR_FIRSTFREESLOT || cnum >= numskincolors)
-			return luaL_error(L, "skincolors[] index %d out of range (%d - %d)", cnum, SKINCOLOR_FIRSTFREESLOT, numskincolors-1);
+		if (!cnum || cnum >= numskincolors)
+			return luaL_error(L, "skincolors[] index %d out of range (1 - %d)", cnum, numskincolors-1);
 		info = &skincolors[cnum]; // get the skincolor to assign to.
 	}
 	luaL_checktype(L, 2, LUA_TTABLE); // check that we've been passed a table.
@@ -1563,14 +1563,19 @@ static int lib_setSkinColor(lua_State *L)
 		} else if (i == 3 || (str && fastcmp(str,"invcolor"))) {
 			UINT16 v = (UINT16)luaL_checkinteger(L, 3);
 			if (v >= numskincolors)
-				return luaL_error(L, "attempt to set skincolors[%d].invcolor to out of range value %d.", cnum, v);
+				return luaL_error(L, "skincolor_t field 'invcolor' out of range (1 - %d)", numskincolors-1);
 			info->invcolor = v;
 		} else if (i == 4 || (str && fastcmp(str,"invshade")))
 			info->invshade = (UINT8)luaL_checkinteger(L, 3)%COLORRAMPSIZE;
 		else if (i == 5 || (str && fastcmp(str,"chatcolor")))
 			info->chatcolor = (UINT16)luaL_checkinteger(L, 3);
-		else if (i == 6 || (str && fastcmp(str,"accessible")))
-			info->accessible = lua_toboolean(L, 3);
+		else if (i == 6 || (str && fastcmp(str,"accessible"))) {
+			boolean v = lua_toboolean(L, 3);
+			if (cnum < FIRSTSUPERCOLOR && v != skincolors[cnum].accessible)
+				return luaL_error(L, "skincolors[] index %d is a standard color; accessibility changes are prohibited.", cnum);
+			else
+				info->accessible = v;
+		}
 		lua_pop(L, 1);
 	}
 	return 0;
@@ -1615,12 +1620,13 @@ static int skincolor_set(lua_State *L)
 	UINT32 i;
 	skincolor_t *info = *((skincolor_t **)luaL_checkudata(L, 1, META_SKINCOLOR));
 	const char *field = luaL_checkstring(L, 2);
+	UINT16 cnum = (UINT16)(info-skincolors);
 
 	I_Assert(info != NULL);
 	I_Assert(info >= skincolors);
 
-	if (info-skincolors < SKINCOLOR_FIRSTFREESLOT || info-skincolors >= numskincolors)
-		return luaL_error(L, "skincolors[] index %d out of range (%d - %d)", info-skincolors, SKINCOLOR_FIRSTFREESLOT, numskincolors-1);
+	if (!cnum || cnum >= numskincolors)
+		return luaL_error(L, "skincolors[] index %d out of range (1 - %d)", cnum, numskincolors-1);
 
 	if (fastcmp(field,"name")) {
 		const char* n = luaL_checkstring(L, 3);
@@ -1633,7 +1639,7 @@ static int skincolor_set(lua_State *L)
 		if (info->name[0] != '\0') // don't check empty string for dupe
 		{
 			UINT16 dupecheck = R_GetColorByName(info->name);
-			if (!stricmp(info->name, skincolors[SKINCOLOR_NONE].name) || (dupecheck && (dupecheck != info-skincolors)))
+			if (!stricmp(info->name, skincolors[SKINCOLOR_NONE].name) || (dupecheck && (dupecheck != cnum)))
 				CONS_Alert(CONS_WARNING, "skincolor_t field 'name' ('%s') is a duplicate of another skincolor's name.\n", info->name);
 		}
 	} else if (fastcmp(field,"ramp")) {
@@ -1644,19 +1650,23 @@ static int skincolor_set(lua_State *L)
 		else
 			for (i=0; i<COLORRAMPSIZE; i++)
 				info->ramp[i] = (*((UINT8 **)luaL_checkudata(L, 3, META_COLORRAMP)))[i];
-		skincolor_modified[info-skincolors] = true;
+		skincolor_modified[cnum] = true;
 	} else if (fastcmp(field,"invcolor")) {
 		UINT16 v = (UINT16)luaL_checkinteger(L, 3);
 		if (v >= numskincolors)
-			return luaL_error(L, "attempt to set skincolor_t field 'invcolor' to out of range value %d.", v);
+			return luaL_error(L, "skincolor_t field 'invcolor' out of range (1 - %d)", numskincolors-1);
 		info->invcolor = v;
 	} else if (fastcmp(field,"invshade"))
 		info->invshade = (UINT8)luaL_checkinteger(L, 3)%COLORRAMPSIZE;
 	else if (fastcmp(field,"chatcolor"))
 		info->chatcolor = (UINT16)luaL_checkinteger(L, 3);
-	else if (fastcmp(field,"accessible"))
-		info->accessible = lua_toboolean(L, 3);
-	else
+	else if (fastcmp(field,"accessible")) {
+		boolean v = lua_toboolean(L, 3);
+		if (cnum < FIRSTSUPERCOLOR && v != skincolors[cnum].accessible)
+			return luaL_error(L, "skincolors[] index %d is a standard color; accessibility changes are prohibited.", cnum);
+		else
+			info->accessible = v;
+	} else
 		CONS_Debug(DBG_LUA, M_GetText("'%s' has no field named '%s'; returning nil.\n"), "skincolor_t", field);
 	return 1;
 }
@@ -1688,11 +1698,11 @@ static int colorramp_get(lua_State *L)
 static int colorramp_set(lua_State *L)
 {
 	UINT8 *colorramp = *((UINT8 **)luaL_checkudata(L, 1, META_COLORRAMP));
-	UINT16 cnum = (UINT16)(((uint8_t*)colorramp - (uint8_t*)(skincolors[0].ramp))/sizeof(skincolor_t));
+	UINT16 cnum = (UINT16)(((UINT8*)colorramp - (UINT8*)(skincolors[0].ramp))/sizeof(skincolor_t));
 	UINT32 n = luaL_checkinteger(L, 2);
 	UINT8 i = (UINT8)luaL_checkinteger(L, 3);
-	if (cnum < SKINCOLOR_FIRSTFREESLOT || cnum >= numskincolors)
-		return luaL_error(L, "skincolors[] index %d out of range (%d - %d)", cnum, SKINCOLOR_FIRSTFREESLOT, numskincolors-1);
+	if (!cnum || cnum >= numskincolors)
+		return luaL_error(L, "skincolors[] index %d out of range (1 - %d)", cnum, numskincolors-1);
 	if (n >= COLORRAMPSIZE)
 		return luaL_error(L, LUA_QL("skincolor_t") " field 'ramp' index %d out of range (0 - %d)", n, COLORRAMPSIZE-1);
 	if (hud_running)