diff --git a/celldrawer.cpp b/celldrawer.cpp
index 8859abdf..35cebf0b 100644
--- a/celldrawer.cpp
+++ b/celldrawer.cpp
@@ -588,7 +588,7 @@ void celldrawer::setcolors() {
   
   if(c->wall == waGlass && !wmspatial) fcol = wcol;  
   
-  if(neon_mode == 4) {
+  if(neon_mode == eNeon::illustration) {
     fcol = highwall(c) ? w_monochromatize(fcol, 0) : w_monochromatize(fcol, 1);
     wcol = w_monochromatize(wcol, 0);
     if(c->land == laWarpCoast && !pseudohept(c) && c->wall == waNone) fcol = 0x707070;
@@ -745,7 +745,7 @@ void celldrawer::draw_wall() {
         }
       else {
         forCellIdEx(c2, i, c) 
-          if(!highwall(c2) || conegraph(c2) || neon_mode == 4) {
+          if(!highwall(c2) || conegraph(c2) || neon_mode == eNeon::illustration) {
           if(placeSidewall(c, i, SIDE_WALL, V, darkena(wcol2, fd, alpha))) break;
           }
         }
@@ -2523,7 +2523,7 @@ void celldrawer::draw() {
     ct6 = ctof(c);
     #endif
     fd = getfd(c);
-    if(neon_mode == 4) fd = 0;
+    if(neon_mode == eNeon::illustration) fd = 0;
     error = false;
     
     setcolors();
diff --git a/config.cpp b/config.cpp
index 8a44649c..058bd79a 100644
--- a/config.cpp
+++ b/config.cpp
@@ -643,7 +643,7 @@ EX void initConfig() {
   addsaver(nilv::nilperiod[1], "nilperiod_y");
   addsaver(nilv::nilperiod[2], "nilperiod_z");
   
-  addsaver(neon_mode, "neon_mode");
+  addsaverenum(neon_mode, "neon_mode");
   addsaver(noshadow, "noshadow");
   addsaver(bright, "bright");
   addsaver(cblind, "cblind");
@@ -1142,16 +1142,15 @@ EX void showGraphConfig() {
           }
         else dialog::addBreak(100);
         
-        dialog::addBoolItem("standard graphics", neon_mode == 0, 'A');
-        dialog::add_action([] { neon_mode = 0; });
-        dialog::addBoolItem("neon mode", neon_mode == 1, 'B');
-        dialog::add_action([] { neon_mode = 1; });
-        dialog::addBoolItem("no boundary mode", neon_mode == 2, 'C');
-        dialog::add_action([] { neon_mode = 2; });
-        dialog::addBoolItem("neon mode II", neon_mode == 3, 'D');
-        dialog::add_action([] { neon_mode = 3; });
-        dialog::addBoolItem("illustration mode", neon_mode == 4, 'E');
-        dialog::add_action([] { neon_mode = 4; });
+        auto neon_option = [&] (string s, eNeon val, char key) {
+          dialog::addBoolItem(XLAT(s), neon_mode == val, key);
+          dialog::add_action([val] { neon_mode = (neon_mode == val) ? eNeon::none : val; });
+          };
+        
+        neon_option("neon mode", eNeon::neon, 'B');
+        neon_option("no boundary mode", eNeon::no_boundary, 'C');
+        neon_option("neon mode II", eNeon::neon2, 'D');
+        neon_option("illustration mode", eNeon::illustration, 'E');
         dialog::addBreak(100);
         dialog::addInfo(XLAT("hint: press Alt while testing modes"));
         dialog::addBreak(100);
@@ -2526,7 +2525,7 @@ EX int read_config_args() {
     }
   else if(argis("-neon")) {
     PHASEFROM(2);
-    shift(); neon_mode = argi();
+    shift(); neon_mode = eNeon(argi());
     }
   else if(argis("-precw")) {
     PHASEFROM(2);
diff --git a/drawing.cpp b/drawing.cpp
index b48e5912..8b10426d 100644
--- a/drawing.cpp
+++ b/drawing.cpp
@@ -2039,21 +2039,37 @@ template<class T, class... U> T& queuea(PPR prio, U... u) {
   }
 #endif
 
-EX int neon_mode = 0;
+/** colorblind mode */
+EX bool cblind;
+
+#if HDR
+enum class eNeon { none, neon, no_boundary, neon2, illustration};
+#endif
+
+EX eNeon neon_mode;
 
 EX void apply_neon(color_t& col, int& r) {
   switch(neon_mode) {
-    case 0: break;
-    case 1: poly_outline = col << 8; col = 0; break;
-    case 2: r = 0; break;
-    case 3: poly_outline = col << 8; col &= 0xFEFEFE; col >>= 1; break;
+    case eNeon::none: 
+    case eNeon::illustration:
+      break;
+    case eNeon::neon: 
+      poly_outline = col << 8; col = 0; 
+      break;      
+    case eNeon::no_boundary: 
+      r = 0;
+      break;
+    case eNeon::neon2:
+      poly_outline = col << 8; col &= 0xFEFEFE; col >>= 1; 
+      break;
     }
   }
 
 #if CAP_SHAPES
 
+/** used when neon_mode is eNeon::illustration */
 EX color_t magentize(color_t x) {
-  if(neon_mode != 4) return x;
+  if(neon_mode != eNeon::illustration) return x;
   int green = part(x,2);
   int magenta = (part(x, 1) + part(x, 3)) / 2;
   int nm = max(magenta, green);
@@ -2095,27 +2111,27 @@ EX dqi_poly& queuepolyat(const transmatrix& V, const hpcshape& h, color_t col, P
     part(col,1) = b; */
     part(col,2) = part(col,3) = (part(col,2) * 2 + part(col,3) + 1)/3;
     }
-  if(neon_mode == 0 || (h.flags & POLY_TRIANGLES)) {
+  if(neon_mode == eNeon::none || (h.flags & POLY_TRIANGLES)) {
     ptd.color = (darkened(col >> 8) << 8) + (col & 0xFF);
     ptd.outline = poly_outline;
     }
   else switch(neon_mode) {
-    case 1:
+    case eNeon::neon:
       ptd.color = (poly_outline & 0xFFFFFF00) | (col & 0xFF);
       ptd.outline = (darkened(col >> 8) << 8) | (col & 0xFF);
       if(col == 0xFF) ptd.outline = 0xFFFFFFFF;
       break;
-    case 2:
+    case eNeon::no_boundary:
       ptd.color = (darkened(col >> 8) << 8) + (col & 0xFF);
       ptd.outline = 0;
       break;
-    case 3:
+    case eNeon::neon2:
       ptd.color = (darkened(col >> 8) << 8) + (col & 0xFF) + ((col & 0xFF) >> 2);
       ptd.outline = (darkened(col >> 8) << 8) + (col & 0xFF);
       if(col == 0xFF) ptd.outline = 0xFFFFFFFF;
       if(poly_outline != 0xFF) ptd.outline = poly_outline;
       break;
-    case 4: {
+    case eNeon::illustration: {
       if(poly_outline && (poly_outline>>8) != bordcolor) {
         ptd.color = magentize(col);
         ptd.outline = 0xFF;
@@ -2128,6 +2144,7 @@ EX dqi_poly& queuepolyat(const transmatrix& V, const hpcshape& h, color_t col, P
       if(ptd.outline & 0xFF) ptd.outline |= 0xFF;
       break;
       }
+    case eNeon::none: ;
     }
   ptd.linewidth = vid.linewidth;
   ptd.flags = h.flags;
@@ -2254,24 +2271,24 @@ EX void queuestr(const transmatrix& V, double size, const string& chr, color_t c
   
 EX void queuestrn(const transmatrix& V, double size, const string& chr, color_t col, int frame IS(0), int align IS(8)) {
   switch(neon_mode) {
-    case 0:
+    case eNeon::none:
       queuestr(V, size, chr, col, frame, align);
       break;
-    case 1: {
+    case eNeon::neon: {
       dynamicval<color_t> c(poly_outline, col << 8);
       queuestr(V, size, chr, 0, frame, align);
       break;
       }
-    case 2: {
+    case eNeon::no_boundary: {
       queuestr(V, size, chr, col, 0, align);
       break;
       }
-    case 3: {
+    case eNeon::neon2: {
       dynamicval<color_t> c(poly_outline, (col << 8) | 0xFF);
       queuestr(V, size, chr, (col & 0xFEFEFE) >> 1, frame, align);
       break;
       }
-    case 4: {
+    case eNeon::illustration: {
       dynamicval<color_t> c(poly_outline, poly_outline);
       if(poly_outline && (poly_outline>>8) != bordcolor) {
         col = magentize(col << 8) >> 8;
diff --git a/system.cpp b/system.cpp
index e605cfd1..1884ba1d 100644
--- a/system.cpp
+++ b/system.cpp
@@ -27,18 +27,17 @@ namespace rg {
   static const char dualmode = 'U';
   static const char heptagons = '7';
   
-  // wrongmode only -- marks 'global' achievements not related to the current mode
+  /** wrongmode only -- marks 'global' achievements not related to the current mode */
   static const char global = 'x'; 
-  // wrongmode only -- change vid.scfg.players then restart_game(rg::nothing) instead
+  /** wrongmode only -- change vid.scfg.players then restart_game(rg::nothing) instead */
   static const char multi = 'm';
-  // wrongmode only -- mark achievements for special geometries/variations
+  /** wrongmode only -- mark achievements for special geometries/variations */
   static const char special_geometry = 'g';
   }
 #endif
 
 EX bool game_active;
 
-EX bool cblind;
 EX bool autocheat;
 EX eWall canvas_default_wall = waNone;