diff --git a/Manuals/SMV_User_Guide/SMV_User_Guide.tex b/Manuals/SMV_User_Guide/SMV_User_Guide.tex
index b67e0b514..ea4ea3a18 100644
--- a/Manuals/SMV_User_Guide/SMV_User_Guide.tex
+++ b/Manuals/SMV_User_Guide/SMV_User_Guide.tex
@@ -6096,11 +6096,9 @@ \chapter{Keyboard Shortcuts}
 \item only translate the scene left and right when the mouse is moved left and right (ignore up and down mouse movement)
 \end{itemize}
 
-\kitem{f}Activates the {\tt ALT}\ key when moving the scene with the mouse.
-Pressing and releasing the {\tt f}\ key then moving the mouse causes the scene to go in and out until the
-mouse button is released.
+\kitem{f}Decrease distance by 25 percent at which fire opacity is one half. This increases fire opaqueness.
 
-\kitem{F}Toggle algorithm for hiding blockage overlaps.
+\kitem{F, ALT f}Increase distance by 25 percent at which fire opacity is one half. This decreases fire opaqueness.
 
 \kitem{g}Toggle the grid visibility.  When the grid display option
 is active, the x, y and z keys may be used to show or hide the
@@ -6130,6 +6128,10 @@ \chapter{Keyboard Shortcuts}
 
 \kitem{ALT k}Toggle device selection.
 
+\kitem{l}Increase the mass extinction coefficient by 25 percent.  This increases smoke opaqueness.
+
+\kitem{L, ALT l}Decrease the mass extinction coefficient by 25 percent.  This decreases smoke opaqueness.
+
 \kitem{m}Switch between meshes in multiple mesh cases.
 
 \kitem{M}Toggle command line scene clipping.  When turned on, the
diff --git a/Source/smokeview/callbacks.c b/Source/smokeview/callbacks.c
index e1758c160..f5f1952aa 100644
--- a/Source/smokeview/callbacks.c
+++ b/Source/smokeview/callbacks.c
@@ -1886,6 +1886,28 @@ void Keyboard(unsigned char key, int flag){
         break;
       }
       break;
+#ifdef pp_OPACITY_SHORTCUTS
+    case 'f':
+    case 'F':
+      if(global_scase.smoke3dcoll.nsmoke3dinfo<=0){
+        printf("***warning: 3D smoke files not present, fire opacity setting not changed\n");
+        break;
+      }
+      if(use_opacity_depth == 0){
+        use_opacity_depth = 1;
+        GLUISmoke3dCB(USE_OPACITY_DEPTH);
+        GLUIUpdateUseOpacityDepth();
+      }
+      if(key2 == 'F' || keystate == GLUT_ACTIVE_ALT){
+        fire_halfdepth *= 1.25;
+      }
+      else{
+        fire_halfdepth /= 1.25;
+      }
+      GLUISmoke3dCB(UPDATE_SMOKEFIRE_COLORS);
+      printf("50%% opacity at depth: %f (m)\n", fire_halfdepth);
+      break;
+#else
     case 'f':
       alt_ctrl_key_state = KEY_ALT;
       break;
@@ -1894,6 +1916,7 @@ void Keyboard(unsigned char key, int flag){
       GLUIUpdateShowHideButtons();
       glutPostRedisplay();
       break;
+#endif
     case 'g':
       switch(keystate){
       case GLUT_ACTIVE_ALT:
@@ -2091,12 +2114,30 @@ void Keyboard(unsigned char key, int flag){
         if(visTimebar==1)PRINTF("Time bar visible\n");
       }
       break;
+#ifdef pp_OPACITY_SHORTCUTS
+    case 'l':
+    case 'L':
+      if(global_scase.smoke3dcoll.nsmoke3dinfo<=0){
+        printf("***warning: 3D smoke files are present, smoke opacity setting not changed\n");
+        break;
+      }
+      if(key2 == 'L' || keystate == GLUT_ACTIVE_ALT){
+        glui_mass_extinct *= 1.25;
+      }
+      else{
+        glui_mass_extinct /= 1.25;
+      }
+      GLUISmoke3dCB(SMOKE_EXTINCT);
+      printf("Mass extinction : %f (m2/kg)\n", glui_mass_extinct);
+      break;
+#else
     case 'l':
     case 'L':
 #ifdef pp_MEMDEBUG
       printf("memory blocks: %i total size: %i\n", COUNTMEMORYBLOCKS(0), (int)GETTOTALMEMORY);
 #endif
       break;
+#endif
     case 'm':
       switch(keystate){
       case GLUT_ACTIVE_ALT:
diff --git a/Source/smokeview/glui_smoke.cpp b/Source/smokeview/glui_smoke.cpp
index ea67cba47..ea17e9588 100644
--- a/Source/smokeview/glui_smoke.cpp
+++ b/Source/smokeview/glui_smoke.cpp
@@ -328,6 +328,14 @@ extern "C" void GLUICreateVolTourList(void){
   }
 }
 
+#ifdef pp_OPACITY_SHORTCUTS
+/* ------------------ GLUIUpdateUseOpacityDepth ------------------------ */
+
+extern "C" void GLUIUpdateUseOpacityDepth(void){
+  CHECKBOX_use_opacity_depth->set_int_val(use_opacity_depth);
+}
+#endif
+
 /* ------------------ UpdateCombineMeshes ------------------------ */
 
 void UpdateCombineMeshes(void){
@@ -610,7 +618,7 @@ extern "C" void GLUI3dSmokeSetup(int main_window){
   SPINNER_emission_factor = glui_3dsmoke->add_spinner_to_panel(PANEL_fire_opacity, "opacity multiplier:", GLUI_SPINNER_FLOAT, &emission_factor, USE_FIRE_ALPHA, GLUISmoke3dCB);
   glui_3dsmoke->add_checkbox_to_panel(PANEL_fire_opacity, "off axis planes", &smoke_offaxis);
   glui_3dsmoke->add_checkbox_to_panel(PANEL_fire_opacity, "adjust opacities", &smoke_adjust);
-  SPINNER_smoke3d_fire_halfdepth->set_float_limits(0.01, 100.0);
+  SPINNER_smoke3d_fire_halfdepth->set_float_limits(0.001, 1000.0);
   CHECKBOX_force_alpha_opaque = glui_3dsmoke->add_checkbox_to_panel(PANEL_fire_opacity, "force opaque", &force_alpha_opaque, FORCE_ALPHA_OPAQUE, GLUISmoke3dCB);
   GLUISmoke3dCB(USE_OPACITY_DEPTH);
 
diff --git a/Source/smokeview/glui_smoke.h b/Source/smokeview/glui_smoke.h
index 732092ea7..0b772c3f5 100644
--- a/Source/smokeview/glui_smoke.h
+++ b/Source/smokeview/glui_smoke.h
@@ -106,6 +106,9 @@ EXTERNCPP void GLUIUpdateFireAlpha(void);
 EXTERNCPP void GLUIUpdateSmoke3dFlags(void);
 EXTERNCPP void GLUICreateVolTourList(void);
 EXTERNCPP void GLUIDeleteVolTourList(void);
+#ifdef pp_OPACITY_SHORTCUTS
+EXTERNCPP void GLUIUpdateUseOpacityDepth(void);
+#endif
 
 #endif
 
diff --git a/Source/smokeview/menus.c b/Source/smokeview/menus.c
index 7c3299ad3..27f0a08f6 100644
--- a/Source/smokeview/menus.c
+++ b/Source/smokeview/menus.c
@@ -11814,8 +11814,10 @@ static int menu_count=0;
     glutAddMenuEntry("  0: reset animation to the initial time", MENU_DUMMY);
     glutAddMenuEntry("  1-9: number of frames to skip", MENU_DUMMY);
     glutAddMenuEntry("  a/ALT a: increase/decrease flow vector length by 1.5", MENU_DUMMY);
+    glutAddMenuEntry("  f/ALT f: increase/decrease 50% fire opacity depth by 1.25", MENU_DUMMY);
     glutAddMenuEntry("  H: toggle  slice and vector slice visibility", MENU_DUMMY);
     glutAddMenuEntry("  I: toggle  visibility of slices in blockages", MENU_DUMMY);
+    glutAddMenuEntry("  l/ALT l: increase/decrease mass extinction coef by 1.25", MENU_DUMMY);
     glutAddMenuEntry("  N: force bound update when loading files (assume fds is running)", MENU_DUMMY);
     glutAddMenuEntry("  p,P: increment particle variable displayed", MENU_DUMMY);
     glutAddMenuEntry("  s,S: increase/decrease interval between adjacent vectors", MENU_DUMMY);
diff --git a/Source/smokeview/options.h b/Source/smokeview/options.h
index 24f0053da..541cf108f 100644
--- a/Source/smokeview/options.h
+++ b/Source/smokeview/options.h
@@ -13,7 +13,8 @@
 
 //#define pp_SHOW_UPDATE      // show what is being updated in the UpdateShowScene routine
 //#define pp_TERRAIN_HIDE     // hide terrain when hiding internal blockages
-//#define pp_OPACITY_DEBUG // output hrrpuv opacity in center of each mesh
+//#define pp_OPACITY_DEBUG    // output hrrpuv opacity in center of each mesh
+#define pp_OPACITY_SHORTCUTS  // add shortcuts for increasing/decreasing opacity depth
 
 //*** options: windows
 
diff --git a/Source/smokeview/renderimage.c b/Source/smokeview/renderimage.c
index af8eccdba..19fd5131e 100644
--- a/Source/smokeview/renderimage.c
+++ b/Source/smokeview/renderimage.c
@@ -836,7 +836,7 @@ int MergeRenderScreenBuffers(int nfactor, GLubyte **screenbuffers){
             }
           }
 
-          char infobuffer[100];
+          char infobuffer[512];
           int ninfobuffer;
           int skip=3, channel=2;
           char fds_label[256], smv_label[256];