  Directionality in a holographic screen may be useful for projecting images to
be seen in complete horizontal parallax. The continuous sequence of views from
an object may be transferred from the object and enlarged at the screen giving
the same appearence of a holographic image. Due to the actual movement of the
object, images in four dimensions may now be produced with a projector whose
spatial dimensions are much smaller than those of the screen. One technique
that allows for this result is the chromatic encoding of views by means of
holographic optical elements. This is demonstrated to be a complete
reproduction of the original light distribution, although its spectral
continuous distribution of colors makes each view monochromatic, not allowing
for a good color reproduction. The resulting system may substitute conventional
holography in some visual applications were registering is not necessary but
only the effect of the phantasmagoric image. Furthermore, it allows for the
enlarging of holographic images, performing also the direct conversion of the
image of a conventional off-axis hologram to a white-light image.
