1.0JHU Engineering Magazinehttps://engineering.jhu.edu/magazine-archiveOf Paper and Permeability - JHU Engineering Magazinerich600338<blockquote class="wp-embedded-content" data-secret="2kegrOTbZs"><a href="https://engineering.jhu.edu/magazine-archive/2018/05/of-paper-and-permeability/">Of Paper and Permeability</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://engineering.jhu.edu/magazine-archive/2018/05/of-paper-and-permeability/embed/#?secret=2kegrOTbZs" width="600" height="338" title="“Of Paper and Permeability” — JHU Engineering Magazine" data-secret="2kegrOTbZs" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script>
/*! This file is auto-generated */
!function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document);
//# sourceURL=https://engineering.jhu.edu/magazine-archive/wp-includes/js/wp-embed.min.js
</script>
https://engineering.jhu.edu/magazine-archive/wp-content/uploads/2018/05/Paper-Permeability_THUMB.jpg300200For decades, preservationists have helped protect historic documents, such as centuries-old maps, by placing them in clear envelopes. Enclosing them in these clear envelopes provides mechanical support to help keep these old, brittle treasures from crumbling while also allowing the public to see and sometimes handle them. But paper degradation isn’t a self-contained event, says Patricia McGuiggan.