Archival ink is an ink which is designed to resist fading and weathering so that it will endure for future enjoyment. As a general rule, this type of ink works best with specially designed archival paper, so that the paper will endure as well. Many art supply companies sell archival ink or ink pens, and some companies also make cartridges for printers. Many digital photographers use these cartridges to produce their professional-grade prints.
In order to successfully endure over time, an ink must have two main properties. Perhaps the most important is the ability to resist fading. Over time, many inks start to slowly fade away, first turning brown and later almost disappearing altogether. An archival ink must also remain fast to the page, ideally, so that exposure to moisture will not cause the ink to run. These abilities are altered by the chemical composition of the ink, with the best inks being relatively pH neutral or slightly alkaline so that they do not interact with our mildly acidic environment.
Many companies make archival inks which are actually dyes. These dyes are designed to change the color of the material they are applied to permanently. In most cases, these dyes will also hold once they are dry. Dyes tend to remain colorfast only so long, however, depending on the materials used to make the dye. For this reason, pigments are growing increasingly popular for archival ink. Pigment is permanently colorfast, bright, and durable, making it an ideal choice for archival material.
Archival dye inks tend to be cheaper, because their base materials are less expensive. Some of these dyes are quite strong and suitable for the needs of most people; they may last, for example, for several generations. Pigment-based versions will be substantially more expensive, but it also confers a greater sense of permanence. Official government documents may be produced with pigmented inks to ensure that they are still readable by future generations.
Many art supply stores carry a range of archival ink pens made by an assortment of companies. The packaging on these pens usually indicates whether they are made with dye or pigment. Some high-end pens will clog with minimal use; only buy such pens when you need them, and try to use them within six months. Archival ink for printers can be purchased from specialty purveyors. Of course, the most enduring writing instrument is actually a pencil; graphite marks can endure for centuries under the right conditions.
