ayscale has a decimal value of 0/128, this difference in intensity you can see in an image.</p>

</li>
</ul>

<pre><code> sub bit_plane {                                    # $type = raw|lsb|msb
   my ($layer,$type) = @_;
   $type = &quot;raw&quot; if not $type;
   my @bit_plane;                                   # resulting bit plane
   my $mask = PDL::Core::pdl(PDL::Core::byte(),
       0b00000001);                                 # initial mask on LSB
   for(my $i=0;$i&lt;=7;$i++) {                      