Flash light has very high uv content which can fade the pigments. The effect is similar to a picture that fades because it’s been exposed to sunlight. I doubt

Flash light has very high uv content which can fade the pigments. The effect is similar to a picture that fades because it’s been exposed to sunlight. I doubt that a day of journalists making pics would have any measurable effect. It’s more a problem if hordes of tourists take pics every day.