Methods for producing a pattern on denim products are disclosed. Patterns may be drawn with either a bleach inhibiting agent or a bleach promoting agent in the forms of a solution or paste. In case the pattern is drawn with a bleach inhibiting agent, the denim product is subjected to bleaching by scrubb­ing in a rotating drum with a plurality of pumices impregnated with a bleaching solution, such as, calcium hypochlorite; or bleaching by immersion and agitation in a bleaching solution. The pattern may remain in dark blue in contrast with the the other portions. In case the pattern is drawn with a bleach promoting agent, the denim product is immersed and agitated in a bleaching solution; and the pattern may be produced as the portion where the pattern was drawn is decolorized faster than the other portions.