Transmission-and reflection-mode holograms each have distinctive characteristics that merit them special roles in holographic imaging applications. For white-light illumination, "rainbow" transmission holograms generally offer brighter and deeper images, with higher resolution, than their reflection analogs. But a significant advantage of reflection holograms is that they can be hung directly on walls, like photographs and paintings, to be illuminated by a simple overhead spotlight. That is, their display format is compatible with established practice in other fine art domains. For non-specialists, especially in homes and small galleries, format familiarity and conservation of space are compelling factors, and severely limit the competitiveness of transmission holograms. Format compatibility also diminishes the "exotic-ness" of holograms, and the visibility of their installation, helping the viewer better appreciate the impact of the holographic three-dimensional image without unnecessary distraction.