  Photonic crystals of close-packed arrays of air spheres in a dielectric
background of titania have been fabricated with a novel ceramic technique.
Unlike previous methods, ordering of the spheres and the formation of the
titania network are performed simultaneously. The photonic crystals exhibit a
reflectance peak and a uniform color at the position of the first stop band.
The wavelength of the reflectance peak scales very well with the sphere size.
