When evaluating Venetian Plaster, you must prioritize material composition and performance metrics. Ensure the product is lime-based (slaked lime) for authentic breathability and mold resistance, or synthetic acrylic-based for higher flexibility and ease of application. Key specs include VOC (Volatile Organic Compounds) levels, which should be low or zero to meet environmental standards, and particle size (fineness), which determines the final gloss and texture. Always request a Technical Data Sheet (TDS) to verify adhesion strength and water vapor permeability.