diff --git a/source/build/src/defs.cpp b/source/build/src/defs.cpp
index 9dca37f0b..ef8e5c74f 100644
--- a/source/build/src/defs.cpp
+++ b/source/build/src/defs.cpp
@@ -118,6 +118,7 @@ enum scripttoken_t
     T_DST_ALPHA, T_ONE_MINUS_DST_ALPHA,
     T_DST_COLOR, T_ONE_MINUS_DST_COLOR,
     T_SHADERED, T_SHADEGREEN, T_SHADEBLUE,
+    T_SHADEFACTOR,
 };
 
 static int32_t lastmodelid = -1, lastvoxid = -1, modelskin = -1, lastmodelskin = -1, seenframe = 0;
@@ -401,6 +402,7 @@ static int32_t defsparser(scriptfile *script)
         { "undefbasepaletterange", T_UNDEFBASEPALETTERANGE },
         { "undefpalookuprange", T_UNDEFPALOOKUPRANGE },
         { "undefblendtablerange", T_UNDEFBLENDTABLERANGE },
+        { "shadefactor",     T_SHADEFACTOR      },
     };
 
     while (1)
@@ -635,6 +637,10 @@ static int32_t defsparser(scriptfile *script)
             if (scriptfile_getnumber(script,&j)) break;
         }
         break;
+        case T_SHADEFACTOR:
+            scriptfile_getnumber(script, &realmaxshade);
+            frealmaxshade = (float)realmaxshade;
+            break;
         case T_ARTFILE:
         {
             char *blockend, *fn = NULL;
diff --git a/source/build/src/palette.cpp b/source/build/src/palette.cpp
index 2a24cd16b..6de6fd50b 100644
--- a/source/build/src/palette.cpp
+++ b/source/build/src/palette.cpp
@@ -314,20 +314,23 @@ void E_PostLoadPalette(void)
         PostLoad_NotFullbright: ;
     }
 
-    uint8_t const * const blackcolor = &palette[blackcol*3];
-    size_t s;
-    for (s = numshades < 2 ? 0 : numshades-2; s > 0; --s)
+    if (realmaxshade == 0)
     {
-        for (size_t c = s*256, c_end = c+255; c < c_end; ++c) // skipping transparent color
+        uint8_t const * const blackcolor = &palette[blackcol*3];
+        size_t s;
+        for (s = numshades < 2 ? 0 : numshades-2; s > 0; --s)
         {
-            uint8_t const index = palookup0[c];
-            uint8_t const * const color = &palette[index*3];
-            if (!IsPaletteIndexFullbright(index) && memcmp(blackcolor, color, sizeof(rgb24_t)))
-                goto PostLoad_FoundShade;
+            for (size_t c = s*256, c_end = c+255; c < c_end; ++c) // skipping transparent color
+            {
+                uint8_t const index = palookup0[c];
+                uint8_t const * const color = &palette[index*3];
+                if (!IsPaletteIndexFullbright(index) && memcmp(blackcolor, color, sizeof(rgb24_t)))
+                    goto PostLoad_FoundShade;
+            }
         }
+        PostLoad_FoundShade: ;
+        frealmaxshade = (float)(realmaxshade = s+1);
     }
-    PostLoad_FoundShade: ;
-    frealmaxshade = (float)(realmaxshade = s+1);
 }
 
 void E_ReplaceTransparentColorWithBlack(void)