An alb is specifically worn by Christian clergy during ceremonies, not by laypeople. The bishop adjusted his alb before the procession.
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Religious Ceremonies
Albs are used in formal religious contexts, particularly in Christian liturgical traditions. Each altar server was dressed in a white alb for the Easter vigil.
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White Symbolism
The color white of an alb often symbolizes purity and is a deliberate choice for religious reasons. During the ceremony, the purity of the celebrant's intention was reflected in his white alb.