The light distribution in the printers is not perfect, but are actually of only slight concern at this time. The contact step printer, if used for making color intermediates on 5253 will automatically almost completely compensate for its own very slight field irregularities. In the continuous printer there is a side to side variation in exposure such that the center transmits about 30% less light than the edges. Note that this is a true side to center variation; this printer knows nothing about corners of the frames so to speak (Fig. 4). This effect, typical of the illumination system in the printer, actually compensates in part for the side to center deficiencies of camera and projector, making the horizon level of the panels more constant in brightness, and reducing the scallop effect. Compare Figs. 1 and 5.

    It is also possible that one side may receive more exposure than the other. This is not serious in our case because use of the mirrors in the projectors results in a “flop over” of the side panel so that the heavy side of one panel is blended into the heavy side of the adjacent panel. (Fig. 6).

    In comparing the contributions to distribution and color errors within a single panel, it is seen that the camera lens contributes most to illumination error, the projector system next and the printer least. The printer somewhat compensating it need not be considered until the total contribution of camera lens and projector system is reduced by a very considerable margin.