Printer friendly styles for the Event Espresso 4 events calendar's iframe. Add the calendar-print-styles.css file to your child theme (top level).

calendar-print-styles.css

@media screen { 
    html { 
        width: 8.5in; 
    }

    body,
    #espresso_calendar .fc-event-title { 
        font: 9pt/1.5 Arial, sans-serif; 
    }
}
@media print {
    html { 
        width: 8.5in; 
    }

    body,
    #espresso_calendar .fc-event-title { 
        font: 9pt/1.5 Arial, sans-serif; 
    }

    .fc-event {
        background: #fff !important;
        color: #000 !important;
    }

    .fc-button,
    #espresso-category-legend,
    .ee-filter-form {
        display: none;
    }
}

functions.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_filter('FHEE__CalendarIframe__display__css', 'add_printer_friendly_calendar_styles', 11, 2);

function add_printer_friendly_calendar_styles(array $stylesheets, $object) {
    $stylesheets['calendar_print_styles'] = get_stylesheet_directory_uri() . DS . 'calendar-print-styles.css';
    return $stylesheets;
}