Here is a little Image::Magick script that may help you analyze image colors. 
#!/usr/bin/perl
use warnings;
use strict;
use Image::Magick;

my $file = shift or die "Need a file $!\n";

my $img = Image::Magick->new;
$img->ReadImage($file);

# if you want a pixel by pixel list of every color
# a huge slow output
#$img->Set(magick => 'txt');
#$img->Write("$0.txt");

#histogram
#returned values are an array of 
#red, green, blue, opacity, and count values.

my $tot = 0;
my (@colors) = $img->Histogram();
#print join "\n\n", @colors;

while (1){
     if (scalar @colors == 0){last}
     my $r = shift @colors;
     my $g = shift @colors;
     my $b = shift @colors;
     my $o = shift @colors;
     my $count = shift @colors; 
     $tot++;
print "$count ($r,$g,$b) at $o opacity\n"; 
}

print "\n$tot total colors\n";

[download]
I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

In reply to Re: check if image is monochromatic by zentara
in thread check if image is monochromatic by frugofrog

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