Art is about many things. It engages the senses and the uniquely human capacity for thought. To be art it must arouse something in us— in its presence we have a response. Surely if we're not aroused it can't be art.
Practitioners of the visual arts work in the paradigms of shape, dimension, color, and the properties of texture, volume, mass and interaction with the work's environment in infinite variation. It's never possible to escape the materiality of the visual conduit to the viewer, or more precisely, participant in the creative communication.
The material elements in art is a far-ranging subject, its relevance to the "art experience" probably isn't fully appreciated. Yet art is conceptually meaningless in the absence of some means to reduce an artist's necessarily private visual imagination to an actual external form for "public" consumption (however "public" is defined).
To state the obvious, physical meterials are the conduit from the abstract, "virtual" image in an artist's mind to the real, concrete form we admire and appreciate. Material physicality is the substrate of the visual "language" of artistic endeavor. In a poetic way, art exists in the realm between the concreteness of things inertly physical and human visual imagination. Artistic achievement reflects the grasp on the significance of that edges of that duality and what binds them together.
In printmaking, materials can occupy a lot of an artist's attention. From the paper selected on up every element of the process has a potential good or bad effect on the outcome. Facing a great array of variables it's hardly surprising when an artist conducts numerous tests along the way to a finished piece or edition.
Among printmakers with an eye for color, the ability to manipulate processes to get a specific result is crucial. "Inks" used in printmaking are extremely varied in terms of the kinds of binders, vehicles and colorants they contain. The artist needs to understand the properties of "inks" intended for use, and very often how to modify these properties to achieve specific effects.
In some cases the artist might even formulate an ink from various source materials to meet requirements. Compared to prior eras, in the 21st century that's probably uncommon, but an artist's ability to create materials like inks is advantageous, perhaps even decisive.
Unfortunately, information about products sold to artists can be hard to come by. Manufacturers often use proprietary ingredients and methods, details about these usually aren't provided to users/artists. At the same time art students may not be offered much in-depth education on the subject, hence students graduate knowing too little about properties of pigments, binders, etc., which affect results and as well have great effect on long-term archival performance of their work.
Ideally artists would be taught about the nature of the materials relevant to their crafts. Creativity is closely linked to innovation and invention. Understanding the gory details will at times enable novel solutions to problems standing in the way of creativity, or even suggest new expressive paradigms that never before existed.