Abstract: The invention relates to a device for obtaining a strip of photosensitive material totally enveloped in a light-tight way. The device comprises a light-tight box provided with two openings which allow the strip to pass therethrough; a cutting member for cutting the strip at a distance D from its end; a connecting member for solidly connecting in a light-tight way and without contact between them, the strip of length D and the rest of the strip coming from the reel using a light-tight material applied to both faces of each strip; and a linking member for linking up the material present on one face and the material present on the other face between the two strips.