Colorless transparency and rapid drying to a water-resistant non-yellowing film are characteristics which makes casein ideal as a pastel fixative.SpectraFix blends art-grade milk casein with water and pure grain alcohol adding a tiny amount of isopropyl alcohol (to please the Federal Government rendering the grain alcohol undrinkable). The alcohol evaporates rapidly taking the water with it, leaving a thin film of casein which quickly dries to a protective matte surface. Even though it is milk protein, it is not subject to invasion by opportunistic organisms, as 9000 years of use as an art medium testifies. SpectraFix is not packaged in a pressurized aerosol can because the necessary propellant required to eject the fixative may cause unforseeable effects to the pastels, your health and the environment. SpectraFix instead uses a Fine Mist Finger Sprayer, producing a vaporous mist through finger action alone. Pastel fixatives on the market today use resin varnishes, propellants and other chemicals as solvents, noticeably darkening the value and shifting the hue, as well as posing health concerns. While it is impossible not to affect the delicate powdery colors of pastels with any kind of spray, even plain water, SpectraFix minimally alters a pastel's value, and does not change the hue. Your colors remain fresh and vibrant, even after several layers. We hope that SpectraFix will be embraced by pastel and crossover technique artists for its light touch and strong grip, with no toxic fumes.