二色调分离法,就是用特硬性或硬性照相制版软片,将普通底片几经拷贝成正片与负片,使中间层次向黑白两极影调并级,最后全部筛除中间层次——灰色调,只留下黑白两级影调。近年来,这种方法在艺术摄影中,颇为流行,也有人研究将其应用在实用摄影中。在艺术摄影的创作中,用这种方法 Two-tone separation method is to use special hard or rigid photographic plate, the ordinary negatives after several copies into positive and negative, so that the middle level to the black and white bipolar video tone and level, and finally all the screen out of the middle level - gray tone, leaving only Black and white two levels of tone. In recent years, this method is quite popular in art photography, and some people study it for practical photography. In the creation of artistic photography, use this method