The Shrine of the Sacred Heart concrete holographic images are recorded onto two superimposed silver halide glass plates each 400 x 300 mm which are sandwiched together and viewed in horizontal format, tilted away from the viewer at the top to a 45 degree angle. The glass plates are mounted into a frame like a lectern to a kneeler.
Both images are reconstructed with 600 milliwatts of yellow coloured 578 nanometre, light from a Copper Vapour laser. The foreground image is of a cross made from light through which passes a flame made from darkness. Beneath this image is a highly ornate 4000 mm diameter geodesic dome embellished in relief with plaster ornamentation and flowers.
The holograms are inside a small chamber. When the chamber is empty the holographic images are reconstructed by white light and laser light from the same reconstruction angle. This is sufficient light to illuminate the chamber and make the lectern kneeler and the edge of the hologram distinguishable. The shallow parts of the image, the cross and flame are visible in the full spectrum with this reconstruction. Like other personal contemplative spaces of St. Brigid's, the image is viewed when kneeling. The holographic plates are mounted to the kneeler.
The parishioner sees the image at first from a standing position. Until the parishioner kneels the holographic images are illuminated with white light and laser light. From the upright position the angle of view through the flame section of the image is most noticeable. The dark contours of the flame are softened by the spectral smear which appears as a rainbow corona in the shape of the flame with a bright white cross behind it. As the parishioner's lower themselves to the kneeler they are continuously within the viewing envelope of the flame image.
Once the pressure of the parishioner's body is registered by the sensor under the kneeler, the white light is dimmed and extinguished. The gradual decrease in the light level is more sudden than the speed of dark adaptability of the parishioner's eyes which directs the parishioner's attention solely on the image, it being the only source of illumination. Three effects occur simultaneously as a result of extinguishing the white light, the image becomes monochromatic in gold, the volume of the image appears to increase significantly and the viewer's chest becomes illuminated with the laser light which passes through the holographic plate. In this position the parishioners forearms are resting on the upper section of the kneeler which places the forearms and hands of the parishioner behind the holographic plate and necessarily within the domain of the virtual image.
When kneeling, a short parishioner's eyes are slightly higher than the top of the holographic plate, the parishioner is at a distance of approximately 400 mm. Both images are laser transmission. The image of the hemisphere is reconstructed entirely behind the plate, whereas the cross image is image planed to reconstruct 20 mm parallel to the plane of the holographic plate and the flame to transverse it, originating at the base of the cross, approximately 40 mm below the holographic plate and extending out into the viewer's space approximately. The parishioner may contemplate for as long as he or she wishes. Once the parishioner stands the pressure is released on the kneeling pad which gradually raises the white light level. The dish image becomes indistinguishable again by the heliacal effect of the flame and cross image. The luminosity of the flame and cross are sufficient to enable the parishioner to exit the chamber into the high ambient light level of the church.
