{"id":185,"date":"2012-01-13T13:07:53","date_gmt":"2012-01-13T19:07:53","guid":{"rendered":"http:\/\/tslacconservation.wordpress.com\/?p=185"},"modified":"2018-06-21T15:08:37","modified_gmt":"2018-06-21T20:08:37","slug":"problem-solving-in-paper-conservation","status":"publish","type":"post","link":"https:\/\/www.tsl.texas.gov\/conservation\/2012\/01\/13\/problem-solving-in-paper-conservation\/","title":{"rendered":"Problem Solving in Paper Conservation"},"content":{"rendered":"

When I talk to new acquaintances about conservation, I receive an alarming number of immediate comparisons with the National Treasure<\/em> films, capers that blend American history, conspiracy theories, and Hollywood glitter.\u00a0 I assure these acquaintances and all current readers that these movies have very little in common with the field of conservation.\u00a0 But in the spirit of adventure films, I\u2019ll begin today\u2019s post with a quote from the fictional, swashbuckling archaeologist Indiana Jones:<\/p>\n

\u201cSnakes.\u00a0 I hate snakes.\u201d<\/p>\n

Why start here?\u00a0 Because Jones\u2019 longstanding antipathy toward his slithering nemeses parallels my professional feelings about an increasingly common foe: the white glue commercially known as Elmer\u2019s.<\/p>\n

For repair purposes, archives typically use water-soluble, reversible adhesives like wheat starch paste.\u00a0 These adhesives are ideal because they allow previous repairs to be undone when needed, such as removing a silk lining from a paper document.\u00a0 Reversibility is a central concept in modern conservation, but this wasn\u2019t always the case.\u00a0 Items that were repaired many years ago, or were repaired by dealers or collectors, were often subjected to whatever materials were on hand.<\/p>\n

Lately, I\u2019ve encountered a number of documents lined with silk and a combination of paste and white glue.\u00a0 At first glance, these documents give no cause for alarm.\u00a0 But once placed in a bath, the linings remain stubbornly adhered in tiny spots all over the document.\u00a0 Closer examination then reveals small, milky-white spots of glue, swelled by the water, but not fully reversed.<\/p>\n

What\u2019s a conservator to do?\u00a0 Simply put, get creative and use chemistry.\u00a0 We know that Elmer\u2019s glue, and white glue in general, is much like the common bookbinding adhesive PVA.\u00a0 And we know that a Teas chart is a tool that maps various solvents according to their solubility parameters.\u00a0 Let\u2019s find a Teas chart for PVA, and then, through careful testing, let\u2019s see if any of the solvents effective on PVA will work on our white glue.\u00a0 Bingo: ethyl acetate.<\/p>\n

Ethyl acetate seems to work best when the white glue has already been swelled with water.\u00a0 It evaporates quickly, so it requires quick, localized work.\u00a0 But I\u2019ve found it to be quite helpful in removing linings and reducing residual adhesive afterwards.\u00a0 Treated items receive a final water bath to flush any remaining solvent.\u00a0 I\u2019d be very curious to hear from other paper conservators any experiences, thoughts, or concerns about using ethyl acetate in this way.<\/p>\n

One last personal observation on white glue: it only seems to appear on high-profile treatments involving especially famous or valuable items.\u00a0 And it appears on these items more regularly than even Murphy\u2019s Law would dictate.\u00a0 My theory is that these highly valued items have been highly valued for many years, and as a result, their past treatments were probably designed to be extra strong.\u00a0 If someone incorrectly thought that a water-soluble adhesive might be a weak adhesive, then perhaps that person might have added some white glue to their paste for good measure.<\/p>\n

Or perhaps I just have bad luck. I\u2019ll watch out for snakes.<\/p>\n","protected":false},"excerpt":{"rendered":"

When I talk to new acquaintances about conservation, I receive an alarming number of immediate comparisons with the National Treasure films, capers that blend American history, conspiracy theories, and Hollywood glitter.\u00a0 I assure these acquaintances and all current readers that … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[20,61],"class_list":["post-185","post","type-post","status-publish","format-standard","hentry","category-conservation-2","tag-conservation","tag-paper"],"_links":{"self":[{"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/posts\/185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/comments?post=185"}],"version-history":[{"count":1,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/posts\/185\/revisions"}],"predecessor-version":[{"id":688,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/posts\/185\/revisions\/688"}],"wp:attachment":[{"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/media?parent=185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/categories?post=185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tsl.texas.gov\/conservation\/wp-json\/wp\/v2\/tags?post=185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}