$COLOR{"0"} = "0 0 0";
$COLOR{"1"} = "0 0 1";
$COLOR{"2"} = "0 1 0";
$COLOR{"3"} = "0 1 1";
$COLOR{"4"} = "1 0 0";
$COLOR{"5"} = "1 0 1";
$COLOR{"6"} = "1 1 0";
$COLOR{"7"} = "1 1 1";
$SY{"0"}    = "0";
$SY{"1"}    = "1";
$SY{"2"}    = "2";
$SY{"3"}    = "3";
$SY{"4"}    = "4";
$SY{"5"}    = "5";
$SY{"6"}    = "6";
$SY{"7"}    = "7";
$SY{"8"}    = "8";
$SY{"9"}    = "9";

open OUT, ">test.ps";
print OUT "%!\n";
print OUT "72 72 scale\n";
print OUT ".25 .25 translate\n";
print OUT "/Courier findfont .095 scalefont setfont\n";


$sy1=1;
$color=0;
for ($y=1; $y<=148; $y++) {
$sy = $sy1; $sy1++; if ($sy1 > 9) {$sy1 = 0;}
for ($x=1; $x<=130; $x++) {

  $_x = $x*.060;
  $_y = $y*.070;

  print OUT "$COLOR{$color} setrgbcolor\n";
  print OUT "$_x $_y  moveto ($SY{$sy}) show\n";
  $sy++; if ($sy > 9) {$sy=0;}
  $color++; if ($color > 7) {$color = 0;}
}
}

print OUT "showpage\n";
close OUT;
`lp test.ps`;
[download]

Hmm.. why use a hash for keys that are just consecutive integers starting at 0? And why write to a temporary file if you can feed the external process directly? Also, Perl knows lists; use the easier to maintain for(@LIST) form of for loops when you don't have special requirements. As well, post-increments return the value a variable had before incrementing it, so you don't need to do that in two steps. Finally, your wrap-around code can be expressed much more naturally using a modulo operation.

use strict;
use warnings;

my @COLOR = (
    "0 0 0",
    "0 0 1",
    "0 1 0",
    "0 1 1",
    "1 0 0",
    "1 0 1",
    "1 1 0",
    "1 1 1",
);

my $postscript = << 'END_POSTSCRIPT';
%!
72 72 scale
.25 .25 translate
/Courier findfont .095 scalefont setfont
END_POSTSCRIPT

my $sy1   = 1;
my $color = 0;

for my $y (1 .. 148) {
    my $sy = $sy1;

    $sy1 %= 10;

    for my $x (1 .. 130) {
        my $_x = $x * .060;
        my $_y = $y * .070;

        $postscript .= "$COLOR{$color} setrgbcolor\n";
        $postscript .= "$_x $_y  moveto ($sy) show\n";

        $sy = ($sy + 1) % 10;
        $color = ($color + 1) % 8;
    }
}

open '|-', my $lp, 'lp'
    or die "Couldn't spawn lp: $!\n";

print $lp $postscript;
[download]

Please use strict and warnings, until you know when you don't need to. This is not just advice to appease the theorists in the ivory tower - making your code work with them will save you many a headache. See

Use strict warnings and diagnostics or die

Use strict warnings and diagnostics

Use strict and warnings

Makeshifts last the longest.