Knowledge Center
What Is Acid Ink? Use in Silk, Wool and Polyamide Printing
Acid ink is an ink class that chemically interacts with protein-based fibers such as wool and silk, and with polyamide fibers such as nylon; it isn't used on cellulosic fibers like cotton, since that bonding mechanism doesn't form there.
How It Works
In acid ink, the dye molecule chemically interacts with protein-based fibers such as wool and silk, or with polyamide fibers such as nylon; this interaction lets the dye bond to the fiber structure through a different mechanism than it would with cellulosic fibers.
How Protein-Based and Polyamide Fibers Behave
Protein-based fibers such as wool and silk, and polyamide fibers such as nylon, have different chemical structures but share a similar bonding mechanism with acid dyes; because of this, acid ink can be used on both fiber groups, though fixation conditions are adjusted for the fiber type.
Why It Doesn't Work on Cellulosic Fibers
Cellulosic fibers such as cotton and linen lack the chemical structure that acid dye can bond to; that's why acid ink is considered only for protein-based and polyamide fibers, not for cotton or blended cellulosic fabrics.
What to Consider When Choosing
The deciding factor when evaluating acid ink is whether the fabric is protein-based (wool, silk) or polyamide-based (nylon); if the fabric has a cellulosic structure, reactive or pigment ink should be considered instead.