How long the fluorescence signal lasts when using an antifade mount medium depends on several factors. Two key factors are the type of antifade mount medium used (if it is soft or hard), and the use of an antifade reagent with a refractive index close to the RI of the glass coverslip. A soft-setting mountant is used for immediate imaging (within 1 hour) and a hard setting mountant is used for long-term storage of cell images (for several years). If the RIs between the mounting medium and cover glass are mismatching, focal point broadening may occur and cause resolution degradation.