diff --git a/config.c b/config.c
index 2fca8bc0..6df95292 100644
--- a/config.c
+++ b/config.c
@@ -2420,9 +2420,9 @@ void setup_config_box(struct controlbox *b, bool midsession,
     ctrl_radiobuttons(s, "Indicate bolded text by changing:", 'b', 3,
                       HELPCTX(colours_bold),
                       conf_radiobutton_handler, I(CONF_bold_style),
-                      "The font", I(1),
-                      "The colour", I(2),
-                      "Both", I(3));
+                      "The font", I(BOLD_STYLE_FONT),
+                      "The colour", I(BOLD_STYLE_COLOUR),
+                      "Both", I(BOLD_STYLE_FONT | BOLD_STYLE_COLOUR));
 
     str = dupprintf("Adjust the precise colours %s displays", appname);
     s = ctrl_getset(b, "Window/Colours", "adjust", str);
diff --git a/putty.h b/putty.h
index 16c4d503..c6295fa1 100644
--- a/putty.h
+++ b/putty.h
@@ -512,6 +512,12 @@ enum {
     CURSOR_BLOCK, CURSOR_UNDERLINE, CURSOR_VERTICAL_LINE
 };
 
+enum {
+    /* these are really bit flags */
+    BOLD_STYLE_FONT = 1,
+    BOLD_STYLE_COLOUR = 2,
+};
+
 enum {
     SER_PAR_NONE, SER_PAR_ODD, SER_PAR_EVEN, SER_PAR_MARK, SER_PAR_SPACE
 };
diff --git a/unix/window.c b/unix/window.c
index 45df2213..f8dbda74 100644
--- a/unix/window.c
+++ b/unix/window.c
@@ -3896,11 +3896,11 @@ static void do_text_internal(
         truecolour.fg = truecolour.bg;
         truecolour.bg = trgb;
     }
-    if ((inst->bold_style & 2) && (attr & ATTR_BOLD)) {
+    if ((inst->bold_style & BOLD_STYLE_COLOUR) && (attr & ATTR_BOLD)) {
         if (nfg < 16) nfg |= 8;
         else if (nfg >= 256) nfg |= 1;
     }
-    if ((inst->bold_style & 2) && (attr & ATTR_BLINK)) {
+    if ((inst->bold_style & BOLD_STYLE_COLOUR) && (attr & ATTR_BLINK)) {
         if (nbg < 16) nbg |= 8;
         else if (nbg >= 256) nbg |= 1;
     }
@@ -3920,7 +3920,7 @@ static void do_text_internal(
         widefactor = 1;
     }
 
-    if ((attr & ATTR_BOLD) && (inst->bold_style & 1)) {
+    if ((attr & ATTR_BOLD) && (inst->bold_style & BOLD_STYLE_FONT)) {
         bold = true;
         fontid |= 1;
     } else {
diff --git a/windows/window.c b/windows/window.c
index 0d1d10d3..21170614 100644
--- a/windows/window.c
+++ b/windows/window.c
@@ -1402,9 +1402,11 @@ static void init_fonts(WinGuiSeat *wgs, int pick_width, int pick_height)
     for (i = 0; i < FONT_MAXNO; i++)
         wgs->fonts[i] = NULL;
 
-    wgs->bold_font_mode = conf_get_int(wgs->conf, CONF_bold_style) & 1 ?
+    wgs->bold_font_mode =
+        conf_get_int(wgs->conf, CONF_bold_style) & BOLD_STYLE_FONT ?
         BOLD_FONT : BOLD_NONE;
-    wgs->bold_colours = conf_get_int(wgs->conf, CONF_bold_style) & 2 ?
+    wgs->bold_colours =
+        conf_get_int(wgs->conf, CONF_bold_style) & BOLD_STYLE_COLOUR ?
         true : false;
     wgs->und_mode = UND_FONT;