diff --git a/src/dehacked.c b/src/dehacked.c
index 6a59df31c..57571b0c0 100644
--- a/src/dehacked.c
+++ b/src/dehacked.c
@@ -11653,6 +11653,8 @@ struct {
 	{"V_70TRANS",V_70TRANS},
 	{"V_80TRANS",V_80TRANS},
 	{"V_90TRANS",V_90TRANS},
+	{"V_ADDTRANS",V_ADDTRANS},
+	{"V_SUBTRANS",V_SUBTRANS},
 	{"V_HUDTRANSHALF",V_HUDTRANSHALF},
 	{"V_HUDTRANS",V_HUDTRANS},
 	{"V_RETURN8",V_RETURN8},
diff --git a/src/hardware/hw_draw.c b/src/hardware/hw_draw.c
index 0fe237e24..69f37a29b 100644
--- a/src/hardware/hw_draw.c
+++ b/src/hardware/hw_draw.c
@@ -141,7 +141,7 @@ void HWR_DrawStretchyFixedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t
 //  0--1
 	float dupx, dupy, fscalew, fscaleh, fwidth, fheight;
 
-	if (alphalevel >= 10 && alphalevel < 13)
+	if (alphalevel >= 12 && alphalevel < 13)
 		return;
 
 	// make patch ready in hardware cache
@@ -268,7 +268,9 @@ void HWR_DrawStretchyFixedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t
 	{
 		FSurfaceInfo Surf;
 		Surf.PolyColor.s.red = Surf.PolyColor.s.green = Surf.PolyColor.s.blue = 0xff;
-		if (alphalevel == 13) Surf.PolyColor.s.alpha = softwaretranstogl_lo[st_translucency];
+		if (alphalevel == 10) { flags &= ~PF_Translucent; flags |= PF_Additive; }
+		else if (alphalevel == 11) { flags &= ~PF_Translucent; flags |= PF_Substractive; }
+		else if (alphalevel == 13) Surf.PolyColor.s.alpha = softwaretranstogl_lo[st_translucency];
 		else if (alphalevel == 14) Surf.PolyColor.s.alpha = softwaretranstogl[st_translucency];
 		else if (alphalevel == 15) Surf.PolyColor.s.alpha = softwaretranstogl_hi[st_translucency];
 		else Surf.PolyColor.s.alpha = softwaretranstogl[10-alphalevel];
@@ -293,7 +295,7 @@ void HWR_DrawCroppedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t pscal
 //  0--1
 	float dupx, dupy, fscale, fwidth, fheight;
 
-	if (alphalevel >= 10 && alphalevel < 13)
+	if (alphalevel >= 12 && alphalevel < 13)
 		return;
 
 	// make patch ready in hardware cache
@@ -426,7 +428,9 @@ void HWR_DrawCroppedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t pscal
 	{
 		FSurfaceInfo Surf;
 		Surf.PolyColor.s.red = Surf.PolyColor.s.green = Surf.PolyColor.s.blue = 0xff;
-		if (alphalevel == 13) Surf.PolyColor.s.alpha = softwaretranstogl_lo[st_translucency];
+		if (alphalevel == 10) { flags &= ~PF_Translucent; flags |= PF_Additive; }
+		else if (alphalevel == 11) { flags &= ~PF_Translucent; flags |= PF_Substractive; }
+		else if (alphalevel == 13) Surf.PolyColor.s.alpha = softwaretranstogl_lo[st_translucency];
 		else if (alphalevel == 14) Surf.PolyColor.s.alpha = softwaretranstogl[st_translucency];
 		else if (alphalevel == 15) Surf.PolyColor.s.alpha = softwaretranstogl_hi[st_translucency];
 		else Surf.PolyColor.s.alpha = softwaretranstogl[10-alphalevel];
diff --git a/src/v_video.c b/src/v_video.c
index 89020eae8..3e2935a46 100644
--- a/src/v_video.c
+++ b/src/v_video.c
@@ -551,7 +551,7 @@ void V_DrawStretchyFixedPatch(fixed_t x, fixed_t y, fixed_t pscale, fixed_t vsca
 		else if (alphalevel == 15)
 			alphalevel = hudplusalpha[st_translucency];
 
-		if (alphalevel >= 10)
+		if (alphalevel >= 12)
 			return; // invis
 
 		if (alphalevel)
@@ -744,7 +744,7 @@ void V_DrawCroppedPatch(fixed_t x, fixed_t y, fixed_t pscale, INT32 scrn, patch_
 		else if (alphalevel == 15)
 			alphalevel = hudplusalpha[st_translucency];
 
-		if (alphalevel >= 10)
+		if (alphalevel >= 12)
 			return; // invis
 
 		if (alphalevel)
@@ -997,7 +997,7 @@ void V_DrawFillConsoleMap(INT32 x, INT32 y, INT32 w, INT32 h, INT32 c)
 		else if (alphalevel == 15)
 			alphalevel = hudplusalpha[st_translucency];
 
-		if (alphalevel >= 10)
+		if (alphalevel >= 12)
 			return; // invis
 	}
 
diff --git a/src/v_video.h b/src/v_video.h
index 49ab33028..7dd44a460 100644
--- a/src/v_video.h
+++ b/src/v_video.h
@@ -120,6 +120,8 @@ void V_CubeApply(UINT8 *red, UINT8 *green, UINT8 *blue);
 #define V_70TRANS            0x00070000
 #define V_80TRANS            0x00080000 // used to be V_8020TRANS
 #define V_90TRANS            0x00090000
+#define V_ADDTRANS           0x000A0000
+#define V_SUBTRANS           0x000B0000
 #define V_HUDTRANSHALF       0x000D0000
 #define V_HUDTRANS           0x000E0000 // draw the hud translucent
 #define V_HUDTRANSDOUBLE     0x000F0000