Color transparency film - The same tri-pack construction as negative film but involves one extra step in order to create a positive image from the negative. After the negative image has been developed, the film is briefly 'exposed' so that the silver compunds that had remained unaltered now form reverse, positive images. A second color development takes place and after this stage, the silver (which is not needed) is bleached away and three color layers are left which give the effect of the original subject colors. See Non-Substantive film.
