While Kodak Portra 800 is a relatively high-speed film, it is generally safe for a single pass through traditional, older-style X-ray scanners used for carry-on luggage. However, the introduction of modern CT (Computed Tomography) scanners at many major airports has changed the risk profile significantly; these high-intensity scanners can "fog" or ruin undeveloped film in a single pass, regardless of the ISO. Because Portra 800 is more sensitive to light and radiation than lower-speed films (like Portra 160 or 400), it is much more susceptible to damage. To protect your shots, you should always place your film in a clear plastic bag and politely request a hand-check from security officers. Most TSA agents in the U.S. and security staff in the UK/EU are trained to honor this request for professional film. Never pack undeveloped film in your checked luggage, as those scanners are far more powerful and will almost certainly destroy your images.