diff --git a/contrib/tools/README.txt b/contrib/tools/README.txt
index 25c68352cb9707a66c81a6390a1e9233797189aa..5ddae02ce9bcc37197f5c6dae25e2daac6836e35 100644
--- a/contrib/tools/README.txt
+++ b/contrib/tools/README.txt
@@ -2,7 +2,7 @@ This directory (contrib/tools) contains tools used by the authors of libpng.
 
 Code and data placed in this directory is not required to build libpng,
 however the code in this directory has been used to generate data or code in
-the body of the libpng source.  The source code idenftifies where this has
+the body of the libpng source.  The source code identifies where this has
 been done.  Code in this directory may not compile on all operating systems
 that libpng supports.
 
diff --git a/contrib/tools/intgamma.sh b/contrib/tools/intgamma.sh
index d2e8ac731e18d9555b24a0f179def6f19c6b35aa..67e4231107c94911e4347a87055ef43a19480162 100644
--- a/contrib/tools/intgamma.sh
+++ b/contrib/tools/intgamma.sh
@@ -9,15 +9,15 @@
 # related or neighboring rights to this work.  This work is published from:
 # United States.
 #
-# Shell script to generate png.c 8 and 16 bit log tables (see the code in png.c
-# for details).
+# Shell script to generate png.c 8-bit and 16-bit log tables (see the code in
+# png.c for details).
 #
-# This script uses the "bc" arbitrary precision calculator to calculate 32 bit
+# This script uses the "bc" arbitrary precision calculator to calculate 32-bit
 # fixed point values of logarithms appropriate to finding the log of an 8-bit
 # (0..255) value and a similar table for the exponent calculation.
 #
-# "bc" must be on the path when the script is executed, the math library (-l)
-# must be available
+# "bc" must be on the path when the script is executed, and the math library
+# (-lm) must be available
 #
 # function to print out a list of numbers as integers; the function truncates
 # the integers which must be one-per-line
@@ -72,8 +72,8 @@ cat <<END
  * each case only the low 16 bits are relevant - the fraction - since the
  * integer bits (the top 4) simply determine a shift.
  *
- * The worst case is the 16-bit distinction between 65535 and 65534, this
- * requires perhaps spurious accuracty in the decoding of the logarithm to
+ * The worst case is the 16-bit distinction between 65535 and 65534; this
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
  * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
  * of getting this accuracy in practice.
  *