There are excellent art media appropriate for pop-ups. Likewise, poor choices will make your work much harder or outright disastrous. The general rules that dictate good choices include: paper compatibility, wrinkle-free application, quick drying, smudge-free, non-sticky, light fast, bright and colorful, high contrast, ease of application, and durability when folded, glued or rubbed.
Good media include watercolor, gouache, alcohol-based colored markers, felt-tipped pens, ball point pens, gel pens, colored pencils, hard graphite, colored paper stock, and stiff but creasable white paper - the latter requiring natural light and shadow to reveal the design.
Poor media choices include oil or dry pastel, thick acrylic paint, oil paint, charcoal, soft graphite, shiny or plastic digital photo paper, paper that cracks when you fold or crease it, thin or flimsy paper, overly fibrous or textured paper, acidic media like cardboard, cheap construction paper, or newsprint, brittle glues, cardstock that is too thick, glues that when cured dissolve in water, and glues that discolor or do not dry clear.
Matte fixative can be used to stabilize certain media so that it will not smudge or stick, but must be applied with care to avoid damaging the artwork and thoroughly off-gassed before closing into a spread. Follow the manufacturer's instructions for safety, and test on a practice piece before deciding if a fixative is appropriate. Many good book ideas have been ruined by a poor choice of media. For example, one student made hers with acrylic paint and, although it appeared to be dry, the spreads bonded shut over time because the acrylic had not fully cured. Dry paint is not the same as cured paint.
Any of the "poor media choices" can be used for the project if the artwork is scanned and printed.
