Though black-tie events call for women to wear dresses, not all dresses are considered appropriate. Fabric is important, and materials such as silk, satin and lace fit in well at formal events. Chiffon is not usually considered a black-tie-appropriate fabric, as it is associated with day dress, but can be appropriate when attending an outdoor black-tie event, such as a summer wedding. Also pay attention to color. Deep jewel tones such as crimson, dark purple and emerald green are appropriate, especially in the fall and winter. Pastels are appropriate for an outdoor event taking place in the spring or summer, and black and white are two classic options any time of year. However, make sure not to wear white if attending a wedding, as this would be considered poor taste.