Topics in Photographic Preservation 1989, Volume 3, Article 10 (pp. 66-68)
It's hard to believe that Post-It Notes have only been around since 1980. Like personal computers and VCR's, they have become so much a part of our environment that they have effected our way of thinking. Just as instant replay has made rapt attention obsolete, and word processors have taken the sting out of spelling errors, yellow sticky tabs have capsulated our thoughts into 16 and 32 word increments.
Yellow tabs are so useful and innocuous that they have developed a market that didn't even exist before they were invented. They show up in books, catalogs, and magazines; on contracts, maps, and letters; and they are posted on every surface in offices, from walls to lamps. There are even computer programs that allow your computer to emulate a yellow sticky tab. In fact, I have observed such a growing dependence on Post-Its at the Geographic that it seems many people actually prefer them even when the adhesive has lost its efficacy. In shooting the slides for this talk, I found Post-Its held in place with tape, paper clips, and even staples.
In addition to their wide use on paper surfaces, they are frequently used on and around photographs at the Geographic: on boxes, sleeves, and other containers; on slide bundles; and on album pages, prints, and even individual slides. They are used by researchers and editors working on stories, by photo lab technicians noting exposures, and even in the photo library.
Post-It Notes come in a variety of sizes and colors, as well as a line of spin-off products carrying the same adhesive, such as Tape Flags, several widths of correction tape, and Removable Magic Tape.
Most of us are familiar with the stories told about the development of the 3M Post-It Note. While doing research into high-tack adhesives, a scientist at 3M discovered a strong yet easily removable adhesive by accident. After several years of sitting on the shelf, in 1974 the adhesive was first put to use by another 3M scientist, to stick bookmarks in his hymnal.
An initial problem with adhesive transfer necessitated reworking the formula, but it wasn't long before the repositionable bookmark caught on among other 3M staff. With further refinements, a commercial product began to emerge and was test-marketed between 1977 and 1979.
Since it appeared on the market, the formula for the adhesive has undergone minor changes, and packaging changes can be used to track the age of the product. For the first two years or so, the backs of the notes were blank. Beginning around 1981, the backs of the notes were printed with the 3M logo, and then after 1985 the mark was changed to the Post-It Note logo.
Changes in the adhesive resulted in improvements relating to characteristics such as sheet removal force and sheer strength, measurements that describe the ability of the adhesive to stick where you put it without sticking too well to the pad. Accelerated aging tests at 3M have shown that the adhesive will never set, and, being an acrylic adhesive, it is extremely stable under adverse environmental conditions.
Last August I discovered the warning on the back of the pack for the first time and became curious about it. The warning is three-fold: first, “May leave a mark on some surfaces;” second, “and lift correctable ink;” and third, “Test before using on questionable paper.”
The second warning is the easiest to deal with, and a relatively small problem at the Geographic, where computers appear to be replacing typewriters completely.
A call to 3M enlightened me regarding the first warning. Apparently the adhesive transfer problem still exists in certain cases. Paper that is clay-coated to better accept printing inks, such as better-quality magazine pages, will cause the notes to leave an adhesive film behind. This is because the notes are primed under the adhesive with a similar coating, and when a note is attached to another clay-coated page, the adhesive may have a stronger affinity for the clay-coated paper than for the primed note.
I found a good example of this after I began collecting books that were returned to our library with yellow sticky tabs still in place. A bound volume of National Geographic Magazine was used to research a TV Special in 1987, and the yellow tabs had been in place for almost two years. When removed, they left a slight adhesive residue that was just detectable to the touch, but which became highly visible when soiled.
The third warning concerns using Post-Its on “questionable paper.” 3M assured me that the adhesive would never cause a problem by bonding with the page to which it is applied, except when applied to the cheaper, ie. ground wood, papers. In fact, one of the books I received from our library was printed in the Soviet Union on a lower grade of paper. There were three Post-Its in the book, one on a coated illustrations page and two on text pages. The tab on the illustration page released easily, leaving a slight residue. The tabs on the text pages, however, pulled paper fibers loose from the surface of the paper. In a month of collecting these books from our library, this was the only instance of this type of damage that I found.
I have learned that heptane and, to a certain extent alcohols such as ethanol and isopropyl alcohol can be used to remove bonded notes and soften adhesive residue, but not having access to analytical equipment at this time, I cannot attest to the safety of such treatments. It would be interesting to test for this, as well as for any interaction with photographic emulsions.
I would like to thank Art Fry, Beth Fritcher, and Judy Borowski of 3M for providing information on the development and characteristics of the product, and Susan Fifer Canby and Arlene Drewes of the NGS Book Library for supporting my research.