Abstract: Photo-composing apparatus comprising a projection system for projecting optical images onto a photo-sensitive recording member by way of a mirror which is rotatable to displace projected images with respect to the recording member, and an element formed by substantially parallel optical fibres between the mirror and the position in which the recording member will be held. The element has first and second major surfaces, the first major surface being concave, and facing the mirror, the second major surface having a radius of curvature substantially greater than that of the first major surface. The optical fibres extending between the first and second major surfaces, and the axis of rotation of the mirror is at the effective centre of curvature of the first major surface.