When sourcing security paper, you must distinguish between True Watermarks (created during the paper-making process by varying fiber density) and Artificial Watermarks (printed with transparent ink). True watermarks offer the highest level of anti-counterfeiting protection as they are visible under both reflected and transmitted light. Additionally, consider integrating security fibers (visible or UV-fluorescent), chemical sensitizers that react to alteration attempts, and embedded security threads to ensure the document's integrity.