diff --git a/lisp/textmodes/artist.el b/lisp/textmodes/artist.el
index e37b0d988ab..686d5f494c9 100644
--- a/lisp/textmodes/artist.el
+++ b/lisp/textmodes/artist.el
@@ -1371,8 +1371,11 @@ Keymap summary
 	(t
 	 ;; Turn mode on
 	 (artist-mode-init)
-         (let ((font (face-attribute 'default :font)))
-           (when (and (fontp font) (not (font-get font :spacing)))
+         (let* ((font (face-attribute 'default :font))
+                (spacing-prop (if (fontp font)
+                                  (font-get font :spacing)
+                                t)))
+           (when (or (null spacing-prop) (eq spacing-prop 0))
              (message "The default font isn't monospaced, so the drawings in this buffer may look odd"))))))
 
 ;; Init and exit
diff --git a/src/xfaces.c b/src/xfaces.c
index d7f1f4d96e5..c41782f4f38 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -1573,7 +1573,14 @@ the face font sort order.  */)
 			     make_fixnum (point),
 			     FONT_WEIGHT_SYMBOLIC (font),
 			     FONT_SLANT_SYMBOLIC (font),
-			     NILP (spacing) || EQ (spacing, Qp) ? Qnil : Qt,
+			     (NILP (spacing)
+			      || EQ (spacing, Qp)
+			      /* If the font was specified in a way
+				 different from XLFD (e.g., on MS-Windows),
+				 we will have a number there, not 'p'.  */
+			      || EQ (spacing,
+				     make_fixnum (FONT_SPACING_PROPORTIONAL)))
+			     ? Qnil : Qt,
 			     Ffont_xlfd_name (font, Qnil),
 			     AREF (font, FONT_REGISTRY_INDEX));
       result = Fcons (v, result);