diff --git a/libpng-manual.txt b/libpng-manual.txt
index 884c196ac..1b1abcdf8 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1660,7 +1660,7 @@ useful:
        png_set_background(png_ptr, image_background,
            PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
     else
-       png_set_background(png_ptr, info_ptr, my_background,
+       png_set_background(png_ptr, my_background,
            PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
 
 The second call was described above - my_background is in the format of the
diff --git a/libpng.3 b/libpng.3
index 93d0540a0..51da7fdb9 100644
--- a/libpng.3
+++ b/libpng.3
@@ -2615,7 +2615,7 @@ useful:
        png_set_background(png_ptr, image_background,
            PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
     else
-       png_set_background(png_ptr, info_ptr, my_background,
+       png_set_background(png_ptr, my_background,
            PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
 
 The second call was described above - my_background is in the format of the