diff --git a/CHANGES.md b/CHANGES.md
index 4686944..fd50944 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -12,7 +12,7 @@ v1.6.1 - YYYY-MM-DD
   indirect reference (Issue #139)
 - Fixed character range checking in a TTF support function.
 - Fixed some clang warnings.
-
+- Fixed the generated pkg-config file.
 
 
 v1.6.0 - 2025-10-06
diff --git a/configure b/configure
index 9efbd75..7d6ab44 100755
--- a/configure
+++ b/configure
@@ -653,7 +653,7 @@ WARNINGS
 CSFLAGS
 LIBPDFIO_STATIC
 LIBPDFIO
-PKGCONFIG_LIBPNG
+PKGCONFIG_REQUIRES_PRIVATE
 PKGCONFIG_REQUIRES
 PKGCONFIG_LIBS_PRIVATE
 PKGCONFIG_LIBS
@@ -4138,7 +4138,9 @@ fi
 PKGCONFIG_CFLAGS="-I\${includedir}"
 PKGCONFIG_LIBS="-L\${libdir} -lpdfio"
 PKGCONFIG_LIBS_PRIVATE="-lm"
-PKGCONFIG_REQUIRES="zlib"
+PKBCONFIG_REQUIRES=""
+PKGCONFIG_REQUIRES_PRIVATE=""
+
 
 
 
@@ -4154,6 +4156,7 @@ then :
 printf "%s\n" "yes" >&6; }
     CPPFLAGS="$($PKGCONFIG --cflags zlib) $CPPFLAGS"
     LIBS="$($PKGCONFIG --libs zlib) $LIBS"
+    PKGCONFIG_REQUIRES_PRIVATE="zlib"
 
 else $as_nop
 
@@ -4216,7 +4219,6 @@ then :
 
 fi
 
-    PKGCONFIG_REQUIRES=""
     PKGCONFIG_LIBS_PRIVATE="-lz $PKGCONFIG_LIBS_PRIVATE"
 
 fi
@@ -4228,9 +4230,6 @@ then :
 fi
 
 
-PKGCONFIG_LIBPNG=""
-
-
 if test "x$PKGCONFIG" != x -a x$enable_libpng != xno
 then :
 
@@ -4246,8 +4245,16 @@ printf "%s\n" "#define HAVE_LIBPNG 1" >>confdefs.h
 
 	CPPFLAGS="$($PKGCONFIG --cflags libpng16) -DHAVE_LIBPNG=1 $CPPFLAGS"
 	LIBS="$($PKGCONFIG --libs libpng16) -lz $LIBS"
-	PKGCONFIG_LIBS_PRIVATE="$($PKGCONFIG --libs libpng16) $PKGCONFIG_LIBS_PRIVATE"
-	PKGCONFIG_REQUIRES="libpng >= 1.6,$PKGCONFIG_REQUIRES"
+	if test "x$PKGCONFIG_REQUIRES_PRIVATE" = x
+then :
+
+	    PKGCONFIG_REQUIRES_PRIVATE="libpng >= 1.6"
+
+else $as_nop
+
+	    PKGCONFIG_REQUIRES_PRIVATE="libpng >= 1.6, $PKGCONFIG_REQUIRES_PRIVATE"
+
+fi
 
 else $as_nop
 
@@ -4314,6 +4321,8 @@ else $as_nop
     LIBPDFIO_STATIC=""
     PKGCONFIG_LIBS="$PKGCONFIG_LIBS $PKGCONFIG_LIBS_PRIVATE"
     PKGCONFIG_LIBS_PRIVATE=""
+    PKGCONFIG_REQUIRES="$PKGCONFIG_REQUIRES_PRIVATE"
+    PKGCONFIG_REQUIRES_PRIVATE=""
 
 fi
 
diff --git a/configure.ac b/configure.ac
index 7a428ac..9d2e057 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,11 +119,13 @@ AC_PATH_TOOL([PKGCONFIG], [pkg-config])
 PKGCONFIG_CFLAGS="-I\${includedir}"
 PKGCONFIG_LIBS="-L\${libdir} -lpdfio"
 PKGCONFIG_LIBS_PRIVATE="-lm"
-PKGCONFIG_REQUIRES="zlib"
+PKBCONFIG_REQUIRES=""
+PKGCONFIG_REQUIRES_PRIVATE=""
 AC_SUBST([PKGCONFIG_CFLAGS])
 AC_SUBST([PKGCONFIG_LIBS])
 AC_SUBST([PKGCONFIG_LIBS_PRIVATE])
 AC_SUBST([PKGCONFIG_REQUIRES])
+AC_SUBST([PKGCONFIG_REQUIRES_PRIVATE])
 
 
 dnl ZLIB
@@ -132,6 +134,7 @@ AS_IF([$PKGCONFIG --exists zlib], [
     AC_MSG_RESULT([yes])
     CPPFLAGS="$($PKGCONFIG --cflags zlib) $CPPFLAGS"
     LIBS="$($PKGCONFIG --libs zlib) $LIBS"
+    PKGCONFIG_REQUIRES_PRIVATE="zlib"
 ],[
     AC_MSG_RESULT([no])
     AC_CHECK_HEADER([zlib.h])
@@ -141,16 +144,12 @@ AS_IF([$PKGCONFIG --exists zlib], [
 	AC_MSG_ERROR([Sorry, this software requires zlib 1.1 or higher.])
     ])
 
-    PKGCONFIG_REQUIRES=""
     PKGCONFIG_LIBS_PRIVATE="-lz $PKGCONFIG_LIBS_PRIVATE"
 ])
 
 dnl libpng...
 AC_ARG_ENABLE([libpng], AS_HELP_STRING([--enable-libpng], [use libpng for pdfioFileCreateImageObjFromFile, default=auto]))
 
-PKGCONFIG_LIBPNG=""
-AC_SUBST([PKGCONFIG_LIBPNG])
-
 AS_IF([test "x$PKGCONFIG" != x -a x$enable_libpng != xno], [
     AC_MSG_CHECKING([for libpng-1.6.x])
     AS_IF([$PKGCONFIG --exists libpng16], [
@@ -158,8 +157,11 @@ AS_IF([test "x$PKGCONFIG" != x -a x$enable_libpng != xno], [
 	AC_DEFINE([HAVE_LIBPNG], 1, [Have PNG library?])
 	CPPFLAGS="$($PKGCONFIG --cflags libpng16) -DHAVE_LIBPNG=1 $CPPFLAGS"
 	LIBS="$($PKGCONFIG --libs libpng16) -lz $LIBS"
-	PKGCONFIG_LIBS_PRIVATE="$($PKGCONFIG --libs libpng16) $PKGCONFIG_LIBS_PRIVATE"
-	PKGCONFIG_REQUIRES="libpng >= 1.6,$PKGCONFIG_REQUIRES"
+	AS_IF([test "x$PKGCONFIG_REQUIRES_PRIVATE" = x], [
+	    PKGCONFIG_REQUIRES_PRIVATE="libpng >= 1.6"
+	], [
+	    PKGCONFIG_REQUIRES_PRIVATE="libpng >= 1.6, $PKGCONFIG_REQUIRES_PRIVATE"
+	])
     ], [
 	AC_MSG_RESULT([no]);
 	AS_IF([test x$enable_libpng = xyes], [
@@ -192,6 +194,8 @@ AS_IF([test x$enable_shared = xyes], [
     LIBPDFIO_STATIC=""
     PKGCONFIG_LIBS="$PKGCONFIG_LIBS $PKGCONFIG_LIBS_PRIVATE"
     PKGCONFIG_LIBS_PRIVATE=""
+    PKGCONFIG_REQUIRES="$PKGCONFIG_REQUIRES_PRIVATE"
+    PKGCONFIG_REQUIRES_PRIVATE=""
 ])
 
 AC_SUBST([LIBPDFIO])
diff --git a/pdfio.pc.in b/pdfio.pc.in
index 7196046..edbca55 100644
--- a/pdfio.pc.in
+++ b/pdfio.pc.in
@@ -11,3 +11,4 @@ Cflags: @PKGCONFIG_CFLAGS@
 Libs: @PKGCONFIG_LIBS@
 Libs.private: @PKGCONFIG_LIBS_PRIVATE@
 Requires: @PKGCONFIG_REQUIRES@
+Requires.private: @PKGCONFIG_REQUIRES_PRIVATE@