The appearance of exposed concrete is occasionally marred by defects which are imparted before the formwork is removed or become visible some time after striking. The photographs found in the article illustrate such blemishes. Defects are listed by their most common names. Photos numbered 1 through 9 exhibit physical irregularities visible immediately after striking the formwork. This includes honeycombing, blowholes, scouring, alignment or profile variation, plastic cracking, form scabbing, spaling or chipping, crazing, and scaling. Possible causes include: poor design of reinforcement; the concrete mix being too lean, too coarse a sand or too low a workability; placing water in formwork or excessively vibrating; rapid or careless placing; inadequate release agents applied; striking time too early; or inadequate curing. Photos number 10 through 18 demonstrate color variations visible immediately or within a few hours of striking the formwork. This includes inherent color variation, aggregate transparency, negative aggregate transparency, dye discoloration, oil discoloration, dusting, retardation, segregation discoloration, and hydration discoloration. Possible causes include: non-uniform color of materials; concrete mix having low sand content; too flexible of formwork used; impure release agent; use of air-set cement; excessive vibration; and non-uniform curing. Photos 19 to 21 show color variations visible only some time after striking the formwork. This includes drying discoloration, efflorescence or lime bloom, and contamination. Some possible causes are: inadequate curing; poor detail design and weathering causing uneven washing by rain; and impurities in the materials such as pyrites and clay.