diff --git a/src/preserves.nim b/src/preserves.nim
index 0d69621..a7db9ab 100644
--- a/src/preserves.nim
+++ b/src/preserves.nim
@@ -1315,7 +1315,7 @@ proc writeText*[E](stream: Stream; pr: Preserve[E]) =
         write(stream, '"')
   of pkSymbol:
     let sym = pr.symbol.string
-    if sym.len > 0 and sym.allIt(char(it) in {'0'..'9', 'A'..'z'}) and sym[0] notin {'0'..'9'}:
+    if sym.len > 0 and sym[0] in {'A'..'z'} and not sym.anyIt(char(it) in { '\x00'..'\x19', '"', '\\', '|' }):
       write(stream, sym)
     else:
       write(stream, '|')
@@ -1325,15 +1325,15 @@ proc writeText*[E](stream: Stream; pr: Preserve[E]) =
           write(stream, "\\\\")
         of '/':
           write(stream, "\\/")
-        of '\x62':
+        of '\x08':
           write(stream, "\\b")
-        of '\x66':
+        of '\x0c':
           write(stream, "\\f")
-        of '\x6e':
+        of '\x0a':
           write(stream, "\\n")
-        of '\x72':
+        of '\x0d':
           write(stream, "\\r")
-        of '\x74':
+        of '\x09':
           write(stream, "\\t")
         of '|':
           write(stream, "\\|")