diff --git a/libpng-manual.txt b/libpng-manual.txt
index c260091b6..d19ac94e8 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -2307,7 +2307,12 @@ with zlib) for details on the compression levels.
     png_set_compression_method(png_ptr, 8);
     png_set_compression_buffer_size(png_ptr, 8192)
 
-extern PNG_EXPORT(void,png_set_zbuf_size)
+    /* set zlib parameters for text compression */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
 
 Setting the contents of info for output
 
@@ -3851,6 +3856,12 @@ PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
 only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
  will lead to a link failure.
 
+Prior to libpng-1.5.3, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.3 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
 B. Changes to the build and configuration of libpng
 
 Details of internal changes to the library code can be found in the CHANGES
diff --git a/libpng.3 b/libpng.3
index 9e886f6b3..98ad76e21 100644
--- a/libpng.3
+++ b/libpng.3
@@ -800,6 +800,26 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.5.3beta02
 
 \fI\fB
 
+\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid \fP\fIpng_set_text_compression_method\fP\fB, (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod)\fP\fB);\fP
+
+\fI\fB
+
 \fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
 
 \fI\fB
@@ -3230,7 +3250,12 @@ with zlib) for details on the compression levels.
     png_set_compression_method(png_ptr, 8);
     png_set_compression_buffer_size(png_ptr, 8192)
 
-extern PNG_EXPORT(void,png_set_zbuf_size)
+    /* set zlib parameters for text compression */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
 
 .SS Setting the contents of info for output
 
@@ -4774,6 +4799,12 @@ PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
 only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
  will lead to a link failure.
 
+Prior to libpng-1.5.3, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.3 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
 B. Changes to the build and configuration of libpng
 
 Details of internal changes to the library code can be found in the CHANGES