diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index b7bd526..7770df6 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -1010,7 +1010,7 @@ QPDFObjectHandle::newString(std::string const& str)
 QPDFObjectHandle
 QPDFObjectHandle::newUnicodeString(std::string const& utf8_str)
 {
-    return {QPDF_String::create_utf16(utf8_str)};
+    return {String::utf16(utf8_str).obj_sp()};
 }
 
 String::String(std::string const& str) :
@@ -1023,6 +1023,16 @@ String::String(std::string&& str) :
 {
 }
 
+String
+String::utf16(std::string const& utf8_str)
+{
+    std::string result;
+    if (QUtil::utf8_to_pdf_doc(utf8_str, result, '?')) {
+        return String(result);
+    }
+    return String(QUtil::utf8_to_utf16(utf8_str));
+}
+
 std::string const&
 String::value() const
 {
diff --git a/libqpdf/QPDF_String.cc b/libqpdf/QPDF_String.cc
index 235cd79..1f883fd 100644
--- a/libqpdf/QPDF_String.cc
+++ b/libqpdf/QPDF_String.cc
@@ -13,16 +13,6 @@ is_iso_latin1_printable(char ch)
     return (ch >= 32 && ch <= 126) || static_cast<unsigned char>(ch) >= 160;
 }
 
-std::shared_ptr<QPDFObject>
-QPDF_String::create_utf16(std::string const& utf8_val)
-{
-    std::string result;
-    if (!QUtil::utf8_to_pdf_doc(utf8_val, result, '?')) {
-        result = QUtil::utf8_to_utf16(utf8_val);
-    }
-    return QPDFObject::create<QPDF_String>(result);
-}
-
 void
 QPDF_String::writeJSON(int json_version, JSON::Writer& p)
 {
diff --git a/libqpdf/qpdf/QPDFObjectHandle_private.hh b/libqpdf/qpdf/QPDFObjectHandle_private.hh
index 4b03f13..0f478a8 100644
--- a/libqpdf/qpdf/QPDFObjectHandle_private.hh
+++ b/libqpdf/qpdf/QPDFObjectHandle_private.hh
@@ -614,6 +614,8 @@ namespace qpdf
         {
         }
 
+        static String utf16(std::string const&);
+
         // Return the string value. If the object is not a valid string, throw a
         // std::invalid_argument exception.
         operator std::string() const&
diff --git a/libqpdf/qpdf/QPDFObject_private.hh b/libqpdf/qpdf/QPDFObject_private.hh
index ecfcf7a..43ad341 100644
--- a/libqpdf/qpdf/QPDFObject_private.hh
+++ b/libqpdf/qpdf/QPDFObject_private.hh
@@ -266,7 +266,6 @@ class QPDF_String final
     friend class qpdf::impl::Writer;
 
   public:
-    static std::shared_ptr<QPDFObject> create_utf16(std::string const& utf8_val);
     std::string unparse(bool force_binary = false);
     void writeJSON(int json_version, JSON::Writer& p);