Taffeta with a silver coating can be exposed to the sun after washing, but it's important to note that exposure to sunlight can cause some fabrics to fade or discolor over time. The exact impact of sunlight on taffeta with a silver coating will depend on several factors, including the specific type of taffeta and the quality of the silver coating.
It's also important to consider the care instructions for your taffeta, as some types of taffeta may be more sensitive to light and heat than others. If your taffeta has a silver coating, it's a good idea to keep it out of direct sunlight whenever possible, and to follow any care instructions provided by the manufacturer.
In general, it's a good idea to protect all fabrics from direct exposure to sunlight, especially for extended periods of time, to help preserve their color and overall appearance.