The getQuantumRange is a useful function, since many of the ImageMagick functions accept parameters from 0 to a maximum of the Quantum Range.  When getting a return value for this, it doesn't return a string.  It actually returns an array, with one type being a String ('quantumRangeLong') and the other type being a Long Int ('quantumRangeString').  Here's some sample code and the results, given a color, BMP file photograph that is 600x450 pixels...

<?php

            // Author: [email protected]
    
        // Imagick Type
        // ---------------------------------------------

    $imagick_type = new Imagick();
    
        // Open File
        // ---------------------------------------------
        
    $file_to_grab = "image_workshop_directory/test.bmp";
    
    $file_handle_for_viewing_image_file = fopen($file_to_grab, 'a+');
    
        // Grab File
        // ---------------------------------------------

    $imagick_type->readImageFile($file_handle_for_viewing_image_file);
    
        // Get Quantum Range
        // ---------------------------------------------
        
    $imagick_type_quantum_range = $imagick_type->getQuantumRange();
    
        // Print Results
        // ---------------------------------------------

    print("<pre>");
    print_r($imagick_type_quantum_range);
    print("</pre>");

?>

Output:

Array
(
    [quantumRangeLong] => 65535
    [quantumRangeString] => 65535
)