918351.fig.008a
(a)
918351.fig.008b
(b)
918351.fig.008c
(c)
918351.fig.008d
(d)
Figure 8: Stable colloid of Y2O3:Eu without UV illumination (a) and when illuminated with UV of wavelength 254 nm (b). Example of writing result using stable luminescent colloid: (c) without illumination with UV and (d) under UV illumination.