“Archival” simply means that something is designed to last a long time, assuming proper care and storage. The most important archival qualities for a print are ink & paper.
Ink: Pigment-based ink is more archival than a dye-based ink. It’s less susceptible to color shifts over time. Also less easily damaged by water, as fine pigment particles are suspended in liquid vs. water-based dyes.
Paper: Acid free paper is best, as acid can damage paper over time. Cotton rag is superior to wood pulp-based paper. It absorbs and holds the ink better for improved colorfastness.
My Process:
First I photograph the original artwork, then edit in Photoshop for digital printing. My printer is a wide format Epson inkjet printer using pigment-based ink. There are actually 9 separate ink cartridges: 4 shades of black, 2 shades of blue, 2 reds and 1 yellow!
I use a heavy acid-free cotton rag watercolor paper, approx. 300#. This paper comes in 17″x40 ft. rolls. Maximum print size is 17″ x 10 ft. ! But usually I print 3-5 feet at a time, then cut into individual cards and prints.