The permanence and archival quality of paper are important considerations for publishers and institutions who feel a responsibility to preserve their legacy for future generations. If a story is important enough to capture in print, it certainly is important enough to be preserved for future generations.
The emergence of acid-free papers
Historically, paper properties presented serious challenges for permanence as the alum and rosin sizing used to resist water in the offset printing process produced paper with very low pH. This caused it to yellow and become extremely brittle with age. Beginning in the 1950’s, alkaline sizing was developed, producing papers at 7.0 – 9.0 pH versus 4.0 to 6.5 pH. Over the following decades, alkaline papermaking has grown steadily. Up until 1986, the alkaline process was used only on specialty papers, marketed as “acid-free” and used by specialty publishers, artists, libraries and other institutions especially concerned with permanence. Toward the turn of the century however, the availability of new sizing agents and low cost fillers allowed more papermakers to convert to alkaline systems and today, most commercially available printing papers are produced with neutral or alkaline pH levels. In 1984, a standard for paper permanence was established by the American National Standard Institute, establishing archival criteria and testing procedures to ensure that if stored under normal conditions, books and documents could be expected to last for several hundred years without deteriorating.
Acid-free vs. alkaline buffered
Earlier, the term “acid-free” was the phrase requested by publishers seeking to avoid the harmful effect of acidic papers. However, as more papers are produced with neutral (7.0) pH, the term isn’t quite as relevant. Premium papermakers like Monadnock take the extra step of “buffering” their papers with calcium carbonate to increase the pH level in an effort to counteract acids migrating to the paper from other materials or the environment. Monadnock Astrolite, Astrolite PC100, Caress and Dulcet are all alkaline buffered and meet ANSI standards for paper permanence
Permanent vs. Archival
You should note that the ANSI standards do not include thickness, opacity, shade or brightness as factors in paper permanence. However, heat, light and humidity can have a detrimental effect on the visual appearance of paper. High-brightness papers in particular are prone to yellowing as their optical dyes are degraded by ultraviolet or fluorescent light. For important fine art books, prints and other artifacts that should be preserved in their original form, it is important to use papers that are free from fading, discoloring or edge yellowing.
Whiteness vs. Brightness
When color accuracy is critical, understand that a balanced shade is more important than the apparent brightness. A current trend is to prefer blue-white papers with optical brightening agents (OBA) that increase the amount of light triggering receptors in the eye (similar to fluorescent paint under a black-light). This increase is in the blue-violet part of the spectrum, so while these papers appear brighter to the eye, they might not reflect other parts of the spectrum as well. This is especially important with photos that are heavy in reds and yellows, such as skintones. The blue cast of a paper can result in images that shift noticeably gray. More importantly regarding archival properties, optical brighteners fade and yellow fairly rapidly.
The papers made by Monadnock Paper Mills are specially designed for accurate color reproduction. Monadnock Astrolite has extremely high brightness, but its shade is cleaner and more balanced than competitive blue-white papers. If you are seeking a perfectly balanced paper to ensure extremely accurate color, Monadnock Dulcet is designed as a neutral, balanced white. It is a preferred choice for art museums, libraries and other institutions that must reproduce priceless works perfectly.
You can learn more about Monadnock papers and request samples at the following link: mpm.com