In the early 1970s, Gallo became concerned about the toxic effects of the epoxy resin fabrication process.  He wearied of donning a mask to protect himself from the dust, heat, and noxious fumes emanating from the translucent, glowing epoxy.  Per Gallo, "It was a stinking, sticky process.  There was nothing beautiful or romantic about it."  In response to these health concerns, Gallo experimented with other artistic mediums, including glass, printmaking, and ceramics.  

In 1970, while serving as the head of the Sculpture Department at the University of Illinois at Urbana-Champaign (UIUC), Gallo also operated a serigraphy, aka silkscreen printing, studio in the Center for Advanced Studies at UIUC; the studio and the resulting "low-relief sculptures" were a natural extension of his printmaking studies with Mauricio Lasansky at the University of Iowa in the late 1950s.  In addition to the serigraphy prints, Gallo also created numerous lithographs and ceramic tile reliefs throughout the 1970s and 1980s. 

In 1972, Gallo studied glass during a stay at the Daum Crystallier in Nancy, France.  He was impressed by artists such as Georges Despret (1862 - 1952) and Emile Galle (1846 - 1904), celebrated for their work in porcelain-like pate de varre ("paste of glass"), a casting technique using ground glass, a binder, and a fluxing medium, then fused by firing.   

Examples of his serigraphs, lithographs, and ceramic tile relief appear below.

"Cast paper is a brilliant medium.  In its unadulterated purity, it is pearlescent.  There are no somber dark tones in its modelled geography.  The relationships of light and dark begin and end in the higher frequencies. . . . "  

In 1978, via a grant from the University of Illinois at Urbana-Champaign, Gallo conducted extensive research in paper casting and developed new techniques at a studio he established outside Urbana, IL.  

When Gallo began experimenting with the idea of paper sculpture, he first created a large figurative relief and cast it in paper, using cotton linter pulp (a processed pulp made from the short, fuzzy fibers left on cottonseeds after the main long fibers are removed).  The initial results were disappointing because shrinkage distorted the shallow relief (of the sculpture).  

To offset the distortion, Gallo developed a restraining system employing hundreds of pounds of gutter spikes supported in heavy screens.  The spikes restrained the castings and allowed forced air to circulate uniformly over the surface of the casting.   This technique provided Gallo the depth he sought for the low-relief sculptures; please see the accompanying photograph.

"A deep line or groove in cast paper is not a dark accent; in direct light it becomes a luminous, scintillating fissure.  What would appear raw in bronze or stone, translates into feathery atmospheric gestures in the whiteness of paper." 

To express the delicate features of individual images, Gallo used multiple types of plant fibers and other materials, within the papermaking process, including abaca and jute fibers, blonde burlap and clay, sisal and cotton fibers, etc.   The combination of these elements created a pletorha of colors and "feels" for the sculptures, ranging from a warm, oatmeal color to a dazzling white, all in varying textures.  

The instructional manuals, one co-authored by Gallo, and the newspaper article from 1988 appearing below demonstrate Gallo's commitment to the science of papermaking and the cast paper sculpture process.